Romans 4:16-17 (NIV)
16 Therefore, the promise comes by faith, so that it may be by grace and may be guaranteed to all Abraham's offspring--not only to those who are of the law but also to those who are of the faith of Abraham. He is the father of us all.
17 As it is written: "I have made you a father of many nations." He is our father in the sight of God, in whom he believed--the God who gives life to the dead and calls things that are not as though they were.

For your information there is a whole theological system that is called promise theology. I do not want to get to technical, however I do think it is important you have some understanding of this system. Basically those that believe in this system see the Bible as one story and that story is connected to the promise that was given to Abram in Genesis 12.

1Now 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. 2I will make of you a great nation, and I will bless you, and make your name great, so that you will be a blessing. 3I will bless those who bless you, and the one who curses you I will curse; and in you all the families of the earth shall be blessed.”£

Notice the last phrase is, "...and in you all the families of the earth shall be blessed." God gave a promise to Abram and God has and is carrying out that promise to it's completion.

The problem with this system and there are problems with all the theological systems is how does the church fit in since this promise was given to Abram a Jew. I believe Paul is answering all those questions in Romans and in Galatians. Because the promise was given and Abram believed, then it is by faith. That is why Paul says, "He is the father of us all." Another problem is how is the promised carried out since the law came along and we have the church. In Ephesians we have this verse. Ephesians 2:12 (NIV)
12 remember that at that time you were separate from Christ, excluded from citizenship in Israel and foreigners to the covenants of the promise, without hope and without God in the world. The key phrase is, "...to the covenants of the promise." The covenants is what distinguishes how God worked in and through Abraham, Moses, and now through the Christ. The covenant is a special agreement between God and His people. In other words how do I know how to connect to Yahweh? The covenant gives the parameters of that relationship. Now what you have is the promise that is carried out by God and to his people through the covenants. There are three covenants and they are the Abrahamic, Mosaic, and the Christ covenant. Trust me this go on and on and on but that is it in a nut shell. I hope you all are have a great week and may God keep your family safe and in His will.