A.T. Robertson Commentary Acts 3:25

"Ye are the sons of the prophets, and of the covenant which God made with your fathers, saying unto Abraham, And in thy seed shall all the families of the earth be blessed." — Acts 3:25 (ASV)

Ye (Hυμεις). Emphatic position.

The covenant which God made (της διαθηκης ης ο θεος διεθετο). Literally, "the covenant which God covenanted." Διαθηκη and διεθετο (second aorist middle indicative of διαθημ) are the same root. See on Mt 26:28. The covenant (agreement between two, δια, τιθημ) was with Abraham (Genesis 12:1–3) and repeated at various times (Genesis 18:18; Genesis 22:18; 26:4, etc.). In Heb 9:15-18 the word is used both for covenant and will. The genitive relative ης attracted to case of the antecedent.