In Matthew 4:15-23, Jesus began his ministry with the Gospel message to repent for the Kingdom of God is at hand, which was a light to the Gentile, and God's law was how his audience knew what sin is (Romans 3:20, so teaching repentance and obedience to it is the Gospel of the Kingdom, which Jesus prophesied would be proclaimed to all nations (Matthew 24:12-14), which was the Gospel of the Kingdom that was made known to advance to Abraham (Galatians 3:8), which means that God's law made known in advance to Abraham, and it was because Abraham lived in accordance with it and busied his life spreading it that all of the promises were made to him and were brought about. The Kingdom of God is where we are being a blessing to others by multiplying the nature of God though teaching others to walk in God's way in obedience to His law. In Genesis 18:19, God's knew Abraham that he might teach his children and those of his household to walk in His way by doing righteousness and justice that the Lord may bring to him all that he has promised, namely in Genesis 26:4-5, God will multiply his children as the starts of the heaven, to his children He will give all of these lands, and through his children all of the nations of the earth shall be blessed because he heard God's voice and guarded His charge, His commandments, His statutes, and His laws, and in Deuteronomy 30:16, all of these promises were also fulfilled of his children being a blessing because they also walk in God's way in obedience to His commandments, statutes, and laws.
In Galatians 3:26-29, being children of Abraham and heirs to the promise is equated with being children of God in Christ through faith, in John 8:39, Jesus said that if they were children of Abraham, then they would be doing the same works that he did, in 1 John 3:4-10, those who do not practice righteousness in obedience to God's law are not children of God, and are thus also not children of Abraham because he walked in God's way by doing righteousness and taught his children to do that, in Romans 3:31, our faith upholds God's law, and in 1 John 2:6, those who are in Christ are obligated to walk in the same way he walked, which was in obedience to God's law, so being children of Abraham being heirs to the promise, being children of God, being in Christ through faith, is all connected with be a blessing by spreading the Gospel of the Kingdom by teaching other to repent from their wickedness and to walk in God's way, and Jesus, who is the living embodiment of God's way (John 14:6), was sent as the ultimate fulfillment of the promise to bless us by turning us from our wickedness.
Genesis 12:1-5 Now the Lord said to Abram, “Go from your country and your kindred and your father's house to the land that I will show you. 2 And I will make of you a great nation, and I will bless you and make your name great, so that you will be a blessing. 3 I will bless those who bless you, and him who dishonors you I will curse, and in you all the families of the earth shall be blessed.” 4 So Abram went, as the Lord had told him, and Lot went with him. Abram was seventy-five years old when he departed from Haran. 5 And Abram took Sarai his wife, and Lot his brother's son, and all their possessions that they had gathered, and the people that they had acquired in Haran, and they set out to go to the land of Canaan.
The souls that they had made in Haran refers making converts. In Romans 9:6-8, not all are children of Abraham because they are his offspring, and it is not children of the flesh who are the children of God, but the children of the promise. In other words, the nation that Abraham is the father of is a nation that is multiplied by making coverts through spreading the Gospel of the Kingdom by teaching people to walk in God's way in obedience to His law, which is teaching others to be children of the promise through faith. In Psalms 119:1-3, God's law is how the children of Abraham knew how live blessed lives by walking in God's way, so the way to fulfill the promise of being a blessing to the nations is by teaching the nations how to live blessed lives, which is spreading the Gospel of the Kingdom. Abraham was justified through faith in the promises of God and He did not randomly pick Abraham to make those promises to, but only made the promises to him because he was busy teaching others how to walk in God's way in obedience to His law, which means that God's law was given to him before he was justified.