The promises were spoken to Abraham and to his seed. The Scripture does not say, “and to seeds,” meaning many, but “and to your seed,” meaning One, who is Christ.
16. Now to Abraham, and his seed. Before pursuing his argument, he introduces an observation about the substance of the covenant, that it rests on Christ alone. But if Christ be the foundation of the bargain, it follows that it is of free grace; and this too is the meaning of the word promise.
The apostle having reproved the Galatians for not obeying the truth, and endeavoured to impress them with a sense of their folly herein, in these verses he largely proves the doctrine which he had reproved them for rejecting, namely, that of justification by faith without the works of the law. This he does several ways. I. From the example of Abraham's justification. This argument the apostle uses, Rom. 4.
Commenting on Galatians 3:6-18
Now to Abraham and his seed were the promises made,.... The promises design the promises of the covenant of grace mentioned in the next verse, which are exceeding great and precious, better than those of any other covenant; and which are all yea and amen in Christ, and are chiefly of a spiritual nature; though all the temporal blessings of God's people come to them...