Genesis 17:19

17:19 God said, “No, Sarah your wife is going to bear you a son, and you will name him Isaac. ¹  I will confirm my covenant with him as a perpetual ²  covenant for his descendants after him.

Genesis 17:21

17:21 But I will establish my covenant with Isaac, whom Sarah will bear to you at this set time next year.”

Romans 9:7-8

9:7 nor are all the children Abraham’s true descendants; rather “through Isaac will your descendants be counted.” ³  9:8 This means ⁴  it is not the children of the flesh ⁵  who are the children of God; rather, the children of promise are counted as descendants.

Hebrews 11:18

11:18 God had told him, “Through Isaac descendants will carry on your name,” ⁶ 

¹ tn Heb “will call his name Isaac.” The name means “he laughs,” or perhaps “may he laugh” (see the note on the word “laughed” in v. 17).

² tn Or “as an eternal.”

³ tn Grk “be called.” The emphasis here is upon God’s divine sovereignty in choosing Isaac as the child through whom Abraham’s lineage would be counted as opposed to Ishmael.

⁴ tn Grk “That is,” or “That is to say.”

⁵ tn Because it forms the counterpoint to “the children of promise” the expression “children of the flesh” has been retained in the translation.

⁶ tn Grk “in Isaac seed will be named for you.”