Galatians 3:12-18 AMP

12 But the Law does not rest on faith [does not require faith, has nothing to do with faith], for it itself says, He who does them [the things prescribed by the Law] shall live by them [not by faith]. [Lev. 18:5.]

13 Christ purchased our freedom [redeeming us] from the curse (doom) of the Law [and its condemnation] by [Himself] becoming a curse for us, for it is written [in the Scriptures], Cursed is everyone who hangs on a tree (is crucified); [Deut. 21:23.]

14 To the end that through [their receiving] Christ Jesus, the blessing [promised] to Abraham might come upon the Gentiles, so that we through faith might [all] receive [the realization of] the promise of the [Holy] Spirit.

15 To speak in terms of human relations, brethren, [if] even a man makes a last will and testament (a merely human covenant), no one sets it aside or makes it void or adds to it when once it has been drawn up and signed (ratified, confirmed).

16 Now the promises (covenants, agreements) were decreed and made to Abraham and his Seed (his Offspring, his Heir). He [God] does not say, And to seeds (descendants, heirs), as if referring to many persons, but, And to your Seed (your Descendant, your Heir), obviously referring to one individual, Who is [none other than] Christ (the Messiah). [Gen. 13:15; 17:8.]

17 This is my argument: The Law, which began 430 years after the covenant [concerning the coming Messiah], does not and cannot annul the covenant previously established (ratified) by God, so as to abolish the promise and make it void. [Exod. 12:40.]

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.