Today, let us prove that the seed promise was fulfilled; that is, all nations have been blessed through Abraham's seed (Gen. 22:18).
Galatians 3:16 is a critical verse to study on this subject - "Now to Abraham and his Seed were the promises made. He does not say, 'And to seeds,' as of many, but as of one, 'And to your Seed,' who is Christ." The reference to Abraham's seed is a reference to Jesus Christ, as the apostle Paul explained. Thus, the initial promise of God in Genesis 22:18, concerning Abraham's seed, simply meant that all the nations of the earth would be blessed through Jesus.
And, has the world been blessed through Jesus? The answer to that question is a resounding yes! But how? The fundamental blessing that Jesus brought to all people of this planet was His sinless life and ministry in which He delivered God's truth and paid the ultimate price, sacrificing Himself to make atonement possible for anyone (I John 2:2). Therefore, the seed promise has been fulfilled through Jesus in that He has made it possible for all mankind to be reconciled to God by grace through faith (Eph. 2). All the world has been blessed with the opportunity to be forgiven of sins through the greatest descendant of Abraham, Jesus the Christ. There is no greater blessing that can be given to all the world than this!
When Jesus returns, those who are faithful will meet Him in the air and will remain with Him forever (I Thess. 4:16,17). Thus, there will be no physical earthly reign for Christ (and hence, the seed promise will not be fulfilled in that manner). Jesus is not going be a blessing to all the world by reigning on a physical throne in the literal city of Jerusalem.
In fact, it can be shown that, according to prophecy, Jesus can never reign on a physical throne in Jerusalem, as some allege. Note the following truths on this point:
Of course, this is not to say that Jesus can't reign at all as a King. He must certainly can reign, and He presently is reigning in heaven! It was predicted that He would sit on David's throne (Luke 1:32,33; Zech. 6:12,13), and this was fulfilled in the spiritual sense God intended (Acts 2:29-36). Jesus is currently reigning in heaven at the right hand of the Father (Rev. 3:21; 4:2ff; Eph. 1:20-23).
Friends, God kept his promise to Abraham. He assured the patriarch that the world would be blessed through his seed, and that is exactly what happened. God is faithful; He keeps His word (Heb. 6:13-18). May we trust Him fully (i.e., without wavering), knowing that He will keep the assurances He has made to His people.