Hebrews 11:18

to whom it was said, "In Isaac shall your seed be called;"

Romans 9:7-8

neither, because they are Abraham's seed, are they all children; but, "In Isaac shall your seed be called."

Treasury of Scripture Knowledge

Summary

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.

Bible References

In isaac

Romans 9:7
neither, because they are Abraham's seed, are they all children; but, "In Isaac shall your seed be called."
Hebrews 11:18
to whom it was said, "In Isaac shall your seed be called;"