All the promises of God find their yes, their fulfillment in Christ. The promise in the Garden to give a Savior, to Abraham to be a father of many nations, to David that his descendant will sit on an eternal throne, and so forth. Jesus fulfills every promise that God makes. All who put their faith in Jesus Christ, that Jesus is God in the flesh, and that Jesus died on the cross and rose again for our salvation, receive righteousness by faith.
The Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, “All the nations will be blessed in you.” So then those who are of faith are blessed with Abraham, the believer.