18 πρὸς (as to) ὃν (whom) ἐλαλήθη (it was said) ὅτι (-), “Ἐν (In) Ἰσαὰκ (Isaac) κληθήσεταί (will be reckoned) σοι (your) σπέρμα (offspring),”
Hebrews 11:18 Cross References - BIB
Romans 9:7
7 οὐδ’ (Nor) ὅτι (because) εἰσὶν (they are) σπέρμα (seed) Ἀβραάμ (of Abraham) πάντες (are all) τέκνα (children); ἀλλ’ (rather), “Ἐν (In) Ἰσαὰκ (Isaac) κληθήσεταί (will be named) σοι (to you) σπέρμα (offspring)”