God is the Author of language, and the ability to communicate by words is one thing that sets apart man from all other creatures. God invented words so He could communicate with us and we can communicate with each other. Figures of speech are an indispensable linguistic component, adding emphasis and feeling to what we say and write.
No one has ever used language as precisely as does its Creator in His God-breathed revelation to mankind. When we recognize the figures of speech in the Bible, we are able to more fully enjoy the richness of the Word of God, and also learn much more truth from it. It is important, therefore, that we become at least somewhat familiar with figures of speech in Scripture, of which there are more than 200 varieties.
We all use such figurative language when we write or speak, often without being aware of it. It helps us to appreciate them, and understand the emphasis they bring to the text, when we recognize them for what they are. The figure of speech that I am going to cover is Polyptoton, which brings powerful emphasis to the subject being discussed, both in speaking and writing. Polyptoton is the repetition of the same word with the same meaning, but in a different case, mood, tense, person, degree, number, gender, etc. 
A wonderful example of Polyptoton occurs early in Genesis, when God is speaking to Adam. By using Polyptoton He gives a strong warning to Adam not to eat of the tree of the knowledge of good and evil.
but you must not eat from the tree of the knowledge of good and evil, for when you eat of it you will surely die.”
The words “surely die” are a translation of the Hebrew mut mut, (the “u” is long), but the first mut is an infinitive form of the verb, while the second is an imperfect form. We would translate the Hebrew literally as, “dying, you will die.” This is a strong statement about the consequences of disobedience. The “surely die” of the NIV carries the sense, but does not have the same feel as the Polyptoton when accurately translated. “Dying, you will die” is an especially strong warning in light of the fact that, out of His goodness and grace, God had just told Adam that he could freely eat of every tree of the Garden, which He also expressed by Polyptoton: “Of every tree of the Garden, eating you will eat” (Gen. 2:16b; author’s translation).
Examples of Polyptoton occur throughout the Bible, in both the Old and New Testament.
- To Eve God said, “…increasing, I will increase your sorrow…” (Gen. 3:16). This is usually translated, “…I will greatly increase your sorrow….”
- God said to Jeremiah, “…weep bitterly for him who is exiled, because he will never return…” (Jer. 22:10b). The Hebrew text reads, “…weeping, weep for him….”
- When Isaac realized he had not blessed Esau, his firstborn, he “trembled violently” (Gen. 27:33). Young’s literal renders that Hebrew, “Isaac trembleth a very great trembling….”
- Numbers records the dissatisfaction some of the Israelites felt about eating manna every day. “The rabble with them began to crave other food… (Num. 11:4a). The Hebrew records their craving more powerfully, using Polyptoton: “And the mixed multitude…lusted a lust.”
- Jesus expressed his great desire to eat the Passover with his disciples: “With desire I desired to eat this Passover with you” (Luke 22:15; author’s translation).
- Paul’s instructions to Timothy have more emphasis because of the Polyptoton. “Timothy, my son, I give you this instruction…that by following them you may fight the good fight” (1 Tim. 1:18).
The above examples are all more or less in the same form, and are easy to see in the original Hebrew or Greek. Other uses of Polyptoton are not as easy to see, but Bullinger gives more than 100 examples in his book on figures of speech, and we can learn to recognize them. Polyptoton is one of the colorful figures of speech that God has used to add emphasis to His Word, and if we pay attention to it, “helping it will help us” get more out of reading our Bible.
 E. W. Bullinger, Figures of Speech Used in the Bible (Baker Book House, Grand Rapids, MI, reprinted 1968), p. 267-285.