And I will establish my covenant between me and you repeats the promise given in Gen 17.2. The verb is different but the sense is the same.

And your descendants after you: God’s promise, or covenant, is to apply not only between God and Abraham, but it will also extend to Abraham’s descendants. After you means “after you die.”

Throughout their generations, which is used in verses 7, 9, 12, is a common expression meaning “all future generations.” The sense is that God’s promise will continue from generation to generation, from one generation to the next.

For an everlasting covenant: this phrase carries the thought still further into the distant future. Everlasting translates a Hebrew word meaning forever, for all time, and is discussed in 9.16. This is a promise that holds good forever, that will never end.

As in verse 4, some translations use a formal introduction to the words of promise that follow; for example, “I make my contract with you… The contract is like this:….”

To be God to you and to your descendants after you: this defines again the promise, as Good News Translation says, “I will be your God and the God of your descendants.” It is not immediately clear what to be God to you means. The covenant refers to numerous descendants and the gift of the land, and it speaks about the relationship between the parties. In languages in which it is not possible to speak of “your God,” it is necessary to state in what way God is related and will be related to Abraham’s descendants here and in Gen 17.8. However, it seems that a future relationship of worship and ritual is being anticipated, or as von Rad says, “… an antedating of the substance of the covenant at Sinai….” We may suggest that God will be the God Abraham and his descendants worship, and so the translation may say “I will be the God you and your descendants worship.” A fuller explanation is given by Driver: “He will be on the one hand the object of their worship and veneration, and on the other hand, also, their lord, their leader, their protector, and their benefactor.”

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .