Treasury of Scripture Knowledge
And God said unto Abraham, Let it not be grievous in thy sight because of the lad, and because of thy bondwoman; in all that Sarah hath said unto thee, hearken unto her voice; for in Isaac shall thy seed be called.
1 Samuel 8:7
The Lord said to Samuel, "Do everything the people request of you. For it is not you that they have rejected, but it is me that they have rejected as their king.
who announces the end from the beginning and reveals beforehand what has not yet occurred, who says, 'My plan will be realized, I will accomplish what I desire,'
God said, "No, Sarah your wife is going to bear you a son, and you will name him Isaac. I will confirm my covenant with him as a perpetual covenant for his descendants after him.
nor are all the children Abraham's true descendants; rather "through Isaac will your descendants be counted."
God had told him, "Through Isaac descendants will carry on your name,"