Cross reference
Hebrews 11:18
18 of whom it was said -- `In Isaac shall a seed be called to thee;'
Genesis 21:12
12 and God saith unto Abraham, `Let it not be wrong in thine eyes because of the youth, and because of thy handmaid: all that Sarah saith unto thee -- hearken to her voice, for in Isaac is a seed called to thee.
Romans 9:7
7 nor because they are seed of Abraham `are' all children, but -- `in Isaac shall a seed be called to thee;'
Genesis 17:19
19 and God saith, `Sarah thy wife is certainly bearing a son to thee, and thou hast called his name Isaac, and I have established My covenant with him, for a covenant age-during, to his seed after him.