And if you belong to Christ [are in Him Who is Abraham’s Seed], then you are Abraham’s offspring and [spiritual] heirs according to promise. Galatians 3:29 (AMPC)
When God promised Abraham that through him the whole world would be blessed He was referring to Christ who came later through the lineage of Abraham. It is through Jesus Christ the Seed of Abraham that God has poured out Salvation, Righteousness and all the resulting blessings to all people in the entire world.
Because we have believed and are now in Christ we are heirs of God’s promise to Abraham.
We are heirs of God. Romans 8:17. God belongs to us.
We are heirs of the Spirit of God. Galatians 3:14. The Holy Spirit lives in us. We are heirs of Eternal Life.Titus3:7. We right now have the very endless life of God. We are heirs of the world. Romans 4:13. The yield, increase, resources, advantages and opportunities of the earth belong to us.