May the grace and peace of God the Father be with you all.
God told Abraham at that time that he should bless him in a way that would make him a great nation, if Abraham proceeded to abandon all his kinship and his land.
Abraham only heard the voice of God and embarked on a long journey of faith and hope. The relevant thing about Abraham's life was the obedience behind his faith. In every word he received from God, Abraham received it, made it his own and obeyed it.
God was so admired of Abraham's obedience that God said:

17 I will truly bless you, and multiply your offspring as the stars of the sky and as the sand that is on the seashore, and your offspring will possess the doors of their enemies. 18 In your descendants all the nations of the earth will be blessed, because you obeyed my voice (Genesis 22: 17-18).

At the end of verse 18, God tells Abraham: "Because you obeyed my voice."
Abraham's obedience that came immediately after his act of faith was something that pleased God. This pleasant obedience to Abraham triggered in his life many important aspects that are mentioned in the verses read.

God told Abraham: "I will truly bless you." The blessing on the material plane led Abraham to be the heir of a great and powerful nation (Israel), where the holy seed (Jesus Christ) would also come from. In that holy seed, God gave Abraham another promise and it was that all the nations of the earth would be blessed. With the sacrifice of Christ on the cross, all mankind was covered by this hope. Today, in every nation there is a remnant of God, through the Lord's church, formed by the people and families that have received from Christ in their hearts. Because of the Lord's church in each nation, the blessing of the nations is evident in the holy seed of Abraham.

God is an extremely extraordinary being in the fulfillment of his promises, which promises that he keeps, if and only if, we obey him as Abraham did.

Some Christians wonder why God has not given them what they have promised, the answer is easy, check their obedience style and you will find the answer to your question.

Abraham's obedience is an example worth following for Christians. Sometimes we say we believe, but our way of acting betrays us and tells us that we are listeners and not doers of the word.
All the blessings of Abraham came into his life because he obeyed the voice of God. Obedience generates results and the results of obedience that comes from hearing the voice of God, unleashes the greatest harvest of blessings that comes from heaven.