Galatians 3:16-19

Amplified Bible

¹⁶ Now the promises [in the covenants] were decreed to Abraham and to his seed. God does not say, “And to seeds (descendants, heirs),” as if [referring] to many [persons], but as to one, “And to your Seed,” who is [none other than] Christ.^{(A) 17} This is what I mean: the Law, which came into existence four hundred and thirty years later [after the covenant concerning the coming Messiah], does not and cannot invalidate the covenant previously established by God, so as to abolish the promise.^{(B) 18} For if the inheritance [of what was promised] is based on [observing] the Law [as these false teachers claim], it is no longer based on a promise; however, God granted it to Abraham [as a gift] by virtue of His promise.

¹⁹ Why, then, the Law [what was its purpose]? It was added [after the promise to Abraham, to reveal to people their guilt] because of transgressions [that is, to make people conscious of the sinfulness of sin], and [the Law] was ordained through angels and delivered to Israel by the hand of a mediator [Moses, the mediator between God and Israel, to be in effect] until the Seed would come to whom the promise had been made.