Galatians 3:18-20

Amplified Bible, Classic Edition

¹⁸ For if the inheritance [of the promise depends on observing] the Law [as these false teachers would like you to believe], it no longer [depends] on the promise; however, God gave it to Abraham [as a free gift solely] by virtue of His promise.

¹⁹ What then was the purpose of the Law? It was added [later on, after the promise, to disclose and expose to men their guilt] because of transgressions and [to make men more conscious of the sinfulness] of sin; and it was intended to be in effect until the Seed (the Descendant, the Heir) should come, to and concerning Whom the promise had been made. And it [the Law] was arranged and ordained and appointed through the instrumentality of angels [and was given] by the hand (in the person) of a go-between [Moses, an intermediary person between God and man].

²⁰ Now a go-between (intermediary) has to do with and implies more than one party [there can be no mediator with just one person]. Yet God is [only] one Person [and He was the sole party in giving that promise to Abraham. But the Law was a contract between two, God and Israel; its validity was dependent on both].