There is no verse of Scripture saying that on the Day of Pentecost God and Jesus were excited and shouting, “Surprise! Happy Birthday!” “Hope you enjoy your present!” Nevertheless, that must have been how they felt that day. God had in mind the “sacred secret,” the Administration of Grace, for thousands of years, but He was the only one who knew. He had hidden it from men, angels, and demons. Good thing, too, for the “present” God gave the Church was so valuable that had Satan known what God was going to do, he would not have crucified Jesus, as the following verse makes clear:
1 Corinthians 2:7 and 8 (Author’s Translation)
(7) But we speak God’s wisdom in a sacred secret, even the wisdom that has been hidden, which God marked out beforehand, before the ages, to our glory,
(8) which none of the rulers of this age knew, for had they known it, they would not have crucified the Lord of glory.
In the Church Epistles, God’s basic curriculum for the Church, He makes it very plain that the Church was a sacred secret, hidden in God. The fact that He calls the Administration of Grace a “sacred secret” should be enough to convince us it was a secret. But we must understand how suspicious it looked to the Jews (and even to others) when the New Testament writers spoke of new things that were not part of the Old Testament. Speaking in tongues, the interpretation of tongues, and the fact that salvation is permanent for Christians were not even hinted at in the Old Testament, so it was very important that the Epistles say over and over that what God did for the Church was a secret, hidden in God.
Romans 16:25b and 26a
(25b) …the mystery [musterion; sacred secret] hidden for long ages past,
(26a) but now revealed and made known through the prophetic writings by the command of the eternal God….
1 Corinthians 2:7 and 10a
(7) No, we speak of God’s secret [musterion; sacred secret] wisdom, a wisdom that has been hidden and that God destined for our glory before time began.
(10a) but God has revealed it to us by his Spirit….
Ephesians 3:4b and 5
(4b) …you will be able to understand my insight into the mystery [musterion; sacred secret] of Christ,
(5) which was not made known to men in other generations as it has now been revealed by the Spirit to God’s holy apostles and prophets.
Ephesians 3:9a (RHM) 
And to bring to light—What is the administration of the sacred secret which had been hidden away from the ages in God….
the mystery [musterion; sacred secret] that has been kept hidden for ages and generations, but is now disclosed to the saints.
On the Day of Pentecost, God began, through His Son Jesus Christ, to pour out His gift of holy spirit. But this was not the same holy spirit that He had given throughout the Old Testament. It was the holy spirit that He promised He would pour out after Christ returned to the earth to Israel, in the Millennial Kingdom. That is why the holy spirit we have today is called the “firstfruits” of the spirit.
Not only so, but we ourselves, who have the firstfruits of the Spirit, groan inwardly as we wait eagerly for our adoption as sons, the redemption of our bodies.
We have the “firstfruits” because what God promised for believers in the Millennial Kingdom, He has now given us by grace. We do not have the same spirit that Old Testament believers had, for then it would not be the “firstfruits” of the spirit.  Furthermore, because in the Old Testament God promised this new holy spirit would be given in the future, what we have is called “the promised Holy Spirit [holy spirit].”
And you also were included in Christ when you heard the word of truth, the gospel of your salvation. Having believed, you were marked in him with a seal, the promised Holy Spirit [holy spirit].
Of course we must remember that God promised this new holy spirit to Israel, not to the Church. We just read six verses that said the sacred secret, the Administration of Grace, was hidden from people in the Old Testament. God promised Old Testament believers that a new spirit would be given in the future Messianic Age, the Millennial Kingdom, but SURPRISE, He gave it to the Church by grace.
In order to understand who we are as Christians and what we have in Christ, we must understand what God did on the Day of Pentecost in Acts 2 when He began the Christian Church. The first thing we must realize is that on Pentecost God poured out His grace upon the Church in a way no people in history had ever experienced. In fact, God actually called the Church Age, the administration in which we live, “the administration of the grace of God,” or as the NIV translates it, “the administration of God’s grace.” 
Surely you have heard about the administration of God’s grace that was given to me for you,
Have you ever looked up “grace” in the Bible? It is a real eye opener to realize that God did not give abundant grace in the Old Testament times like He does today. For example, in the New American Standard Bible  and the English Standard Version,  both modern literal versions, the word “grace” appears 131 times.  In the NASB, eight of those are in the Old Testament, five are in the Gospels, and two are in the book of Revelation, which is written about a time after the Rapture of the Church. That means “grace” appears in the writings to the Church 116 times, as compared with 15 for the entire rest of the Bible! No wonder God calls this administration “…the administration of the grace of God….”
By reading the entire Bible, we Christians can see how God has poured out His grace upon us in a way like never before. No wonder God says we Christians are blessed in a unique way.
Ephesians 1:3 (ESV)
Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with every spiritual blessing in the heavenly places,
At no other time in history, not even when Jesus walked the earth, did God, Jesus, or the Bible say that people were blessed with all the spiritual blessings that God had in the heavenly places.
Let’s stop and think about the best gift that God could ever give a person. If you are thinking salvation, I agree, but I would preface it with the word permanent. Think about it. Salvation, everlasting life, is a great gift, but if there is anything at all on my part that I must do in order to keep it, then honestly, I would always worry a little that I might not make it into Christ’s kingdom. In this “grace” administration, our salvation is permanent. Once a person is saved, he cannot lose that salvation.
That is a change from what God had done prior to the Church Age. Before the New Birth and the gift of the new holy spirit, God never made anyone a guarantee that if they kept the law, did good works, or had faith on a one-time basis, they would be saved. He simply did not make permanent salvation available before Pentecost. To best understand this, it is important that we correctly understand salvation, which is too often misunderstood by Christians. Both Christians and Scripture speak as if Christians are “saved” now. We say, “I am saved,” and we ask people, “Are you saved?” Of course we get this language from Scripture. For example, Ephesians 2:8a says, “For it is by grace you have been saved, through faith….” So there are verses of Scripture that say we have already been saved, and thus it is not wrong to speak that way as long as we understand exactly what we are actually saying.
A close examination of Scripture and the biblical languages shows that we are not actually saved now. The Bible uses an idiom, the “prophetic perfect,” when it says we are saved now. When God guarantees that something will absolutely happen in the future, the Bible sometimes emphasizes that by saying it has already happened. Thus Ephesians 2:6 says we are already in heaven though we are not, and Jude 14 says (in the Greek) that Jesus has already come in Judgment with thousands of his saints, even though that day is still future. Saying that we are already saved when we are not is a biblical way of saying our salvation is certain, though it has not yet been accomplished.
What we have right now, here on earth, is God’s promise that we will be saved. Because God cannot lie, His promise that we will be saved will come true, and because we will absolutely be saved in the future, God speaks about it as if it had already occurred. Knowing that we are not literally saved right now helps us understand verses such as Romans 13:11, which says that our salvation is nearer now than when we first believed; 1 Thessalonians 5:8, which says that what we have is the “hope” of salvation; or 1 Peter 1:5, which says our salvation is “…ready to be revealed in the last time.”
Actually, the fact that we are not yet “saved” is self–evident. Biblically, “saved” means “rescued,” and thus also it means “made whole.” But here on earth we get sick, sad, depressed, hurt, victimized, and die. That is not being saved. Being saved will be when we are in our new bodies, perfectly healthy and fit, full of energy and joy, and will never die. That is the consummation of our salvation, and that is what we will have in the future. It is important to understand what salvation is in order to talk about it correctly.
For example, because the Bible says that as a Christian I have the absolute guarantee of salvation I often say, “I cannot lose my salvation.” But let us address that phrase, because people often ask me if Old Testament believers could “lose” their salvation. Although for ease of communication we sometimes use that phrase, it is not technically correct, because Old Testament believers never had salvation in the first place. What they did have was a promise that if they kept their faith and were righteous by their works, they would be saved in the future.
Thus, we speak of David being saved, or Ruth being saved, because they remained righteous throughout their lives. In actuality they were not “saved,” but we refer to them as such because we know they will be in the “Resurrection of the Righteous” (Luke 14:14; Acts 24:15) and will be saved at that time. But when it comes to someone like Solomon, who was righteous before God for years but then turned against Him and “…did evil in the eyes of the LORD…” (1 Kings 11:6), we are not so sure that he will be saved. If Solomon is not in the Resurrection of the Righteous, it will not be because he “lost” his salvation. No, he never had it. What he did have was a promise that if he lived righteously he would be saved.
Once we understand that, we are in a position to see how totally differently God deals with us than He did with people before the Day of Pentecost. In summary, what we will see is that today, when a person makes Jesus Christ his personal Lord and believes God raised him from the dead, he or she at that moment receives the gift of holy spirit born and sealed inside them. That holy spirit then becomes the guarantee of salvation. Wow, is that grace!
We see the difference in salvation before and after Pentecost in the doctrinal statements about salvation relative to each time period. For example, consider the following verse to people living in the Administration of the Sacred Secret:
That if you confess with your mouth, “Jesus is Lord,” and believe in your heart that God raised him from the dead, you will be saved.
On a technical note, the verbs “confess” and “believe” are in the aorist tense in Greek, which makes reference to the fact of the action, and that the action is attained.  In other words, you have to confess and believe once; you do not have to keep doing it. If we had to keep confessing over and over, something such as a present participle or the present indicative active verb would have been used. In stark contrast to the one-time action that produces the guarantee of salvation in the Grace Administration, the Mosaic Law made it clear that continued obedience (or the continued faith that produced obedience) was necessary for salvation:
“And if we are careful to obey all this law before the LORD our God, as he has commanded us, that will be our righteousness.”
Throughout the Old Testament and Gospel periods there was no one-time action that a person could take that produced a guarantee of salvation. That is why there is no verse before the book of Acts that says a person can get saved by a one-time action. However, when a person in the Administration of Grace professes Jesus as Lord, that person is immediately “born again” by receiving the gift of holy spirit.
Ephesians 1:13 (ESV)
In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit [holy spirit],
That verse makes it very clear that in the Grace Administration, each person who believes is immediately sealed with the promised gift of holy spirit, which is the guarantee of his future salvation. Obviously, the fact that Christians have a guarantee of their salvation is completely different from the way salvation had worked for the 4,000 years before Pentecost. Therefore, it makes sense that God would have to say it very clearly, and more than once, for people to actually believe it. Thankfully, He did just that:
2 Corinthians 1:22
[God] set his seal of ownership on us, and put his Spirit in our hearts as a deposit, guaranteeing what is to come. 
2 Corinthians 5:5
Now it is God who has made us for this very purpose and has given us the Spirit as a deposit, guaranteeing what is to come.
[the promised holy spirit] who [which] is a deposit guaranteeing our inheritance until the redemption of those who are God’s possession—to the praise of his glory.
Notice that in all the above verses, the gift of holy spirit is a deposit that guarantees what will come in the future, in this case, our salvation. There are no verses like these in the Old Testament or the Gospels, because only in the Administration of Grace is salvation guaranteed on the basis of a one-time action, that of taking Christ as our Lord.
It would seem logical that if it really is true that Christians cannot lose their promise of salvation for any reason, there would be more than a few verses saying so—and there are. We have seen Romans 10:9, and the three verses that translate the Greek word arrabon as a “deposit” guaranteeing what is to come. But God says our salvation is permanent in lots of other ways as well. He says we are “born again,” and everyone knows that birth is a one-time event that is permanent. In fact, God uses three different words for birth: annagennao (1 Pet. 1:3, 23); paliggenesia (Titus 3:5); and apokueo (James 1:18). None of these are used of spiritual birth outside the writings to the Christian Church. God also says Christians are adopted into His family, and in the Roman world, adoption was permanent.
We are born of God, so we are said to have his “seed” in us (1 Pet. 1:23) and thus be partakers of God’s divine nature (2 Pet. 1:4). Because we have God’s seed and His nature, we are all “holy ones” (usually translated “saints”). Furthermore, because God creates holy spirit in us, we are said to be new creations in Christ (2 Cor. 5:17; Gal. 6:15). We are said to be seated in the heavenly places with Christ, not because we are actually there, but because we have a guarantee that we will be seated there in the future. We are told that we are already citizens of heaven (Phil. 3:20). These could be expanded upon, but the point should be clear—God has plainly revealed that Christians have a guarantee of salvation.
Why are there so many clear statements that salvation is guaranteed for the Christian while not one such declaration occurs in the Old Testament or the Gospels? Because there was no one-time action that a person living during the Old Testament or Gospel periods could take that guaranteed him salvation. Today, however, in the Age of Grace, when a person confesses Jesus is Lord and believes God raised him from the dead, he immediately is guaranteed salvation, everlasting life in the Kingdom of Christ.
We need to remember one more thing about our guarantee of salvation. It was not foretold in the Old Testament or the Gospels, and was revealed only to the Church. No Old Testament prophet spoke of the Administration of Grace, and no biblical writer told of a time when God would suddenly give humans a guarantee of salvation based on our one-time acceptance of Christ. As Corinthians says: “…No eye has seen, no ear has heard, no mind has conceived what God has prepared for those who love him’—but God has revealed it to us by his Spirit…” (1 Cor. 2:9b and 10a). Who knows? Maybe the Lord did shout from heaven some 2,000 years ago: “Surprise! Happy Birthday, Church! How does it feel to have a guarantee of your salvation?!”
 Scripture quotations marked (RHM) are taken from the Emphasized Bible by Joseph Bryant Rotherham. Kregal Publications, Grand Rapids, MI, reprinted 1994. Rotherham properly translates the Greek word musterion as “sacred secret” in all its occurrences.
 The gift of holy spirit that we have today is so different from the gift of holy spirit God gave to people in the Old Testament that John 7:39 says, “…for as yet there was no Spirit [spirit]….” For a much fuller explanation of John 7:39, see our book, The Gift of Holy Spirit: The Power to be Like Christ, pp. 45 and 46.
 The Greek word “oikonomia” in this verse is a noun, and refers to the Administration of Grace, a time period that runs from Pentecost to the Rapture. The verse is not saying that Paul wanted the Ephesians to know that God had called him to steward God’s grace, because we have all been called to administer the grace of God (1 Pet. 4:10).
 Scripture quotations marked (NASB) are taken from the New American Standard Bible®, © 1960, 1962, 1963, 1968, 1971, 1972, 1973, 1975, 1977, 1995 by The Lockman Foundation. Used by permission.
 Scripture quotations marked (ESV) are taken from The Holy Bible, English Standard Version™ © 2001 by Crossway Bibles, a division of Good News Publishers. All rights reserved.
 The King James Version translates more Hebrew words as “grace,” and so “grace” appears 170 times, but quite a few of them refer to people giving grace to other people.
 H. E. Dana and Julius Mantey, A Manual Grammar of the Greek New Testament (The MacMillan Company, Toronto, Canada, 1957), p. 193.
 A study of the Greek word arrabon will show that it is in fact a deposit that guarantees the delivery of the thing promised. Interestingly, in modern Greek, an arrabona is an engagement ring, “guaranteeing” if you will, the future marriage (Vine’s Lexicon).