One cannot overstate the impact of Genesis 12:1-3:
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."
In those verses, God calls Abram to go forth to a place yet unnamed, and Abram sets out, not sure of his final destination. Abram goes confident God will tell him when he arrives, and indeed, He does (Genesis 12:6-7).
Notice the last line of 12:3: "In you all the families of the earth will be blessed." In my study of this text the past few years, I've begun to realize the profound implications of both God's announcement and of Abram's faithful obedience. The rest of Scripture--Old Testament AND New Testament--essentially spends its time unpacking the implications of God's call on Abram. Everything, and I mean everything, flows from that call.
This statement may seem overstated to some, but I'm more and more convinced it's true. Matthew 1:1 links the birth of the Lord Jesus with Abram, or Abraham as he is later re-named (Genesis 17:5). Paul says the Scripture preached the gospel beforehand to Abraham, and cites Genesis 12:3 as proof (Galatians 3:8). In other words, Abraham did not have understood it as clearly as we do on this side of the incarnation, the cross, the empty tomb, and the New Testament, but he knew he was part of something much bigger than he himself. And as he yielded himself to God's purpose, God blessed Abraham's faith beyond the man's wildest dreams.
Abraham stands as an example of faith for later generations to follow (Isaiah 51:2; Romans 4; Hebrews 11:8-12). Eternity will also remember him; as history as we know it concludes and the new Jerusalem appears for the saints of God, we note that the names of Abraham's twelve great-grandchildren adorn the city's twelve gates (Revelation 21:12). Genesis 12:1-3 announces what the rest of Scripture unpacks--the grand purpose of God to reach the nations with the message of Christ.