1 When Abram was ninety-nine years old, the LORD appeared to him and said, “I am God Almighty; walk before me faithfully and be blameless. 2 Then I will make my covenant between me and you and will greatly increase your numbers.”
3 Abram fell facedown, and God said to him, 4 “As for me, this is my covenant with you: You will be the father of many nations. 5 No longer will you be called Abram; your name will be Abraham, for I have made you a father of many nations. 6 I will make you very fruitful; I will make nations of you, and kings will come from you. 7 I will establish my covenant as an everlasting covenant between me and you and your descendants after you for the generations to come, to be your God and the God of your descendants after you. 8 The whole land of Canaan, where you now reside as a foreigner, I will give as an everlasting possession to you and your descendants after you; and I will be their God.”
I AM GOD ALMIGHTY. Here Yahweh speaks to Abram with an affirmation of his identity, his authority and a sense of command: walk before me and be blameless.
The weighty announcement of Yahweh, God Almighty provokes a response from Abram that emphasises the authority of the speaker - Abram falls facedown.
This is apparently 13 years after Ishmael's birth, when Abram is 99. Yahweh, it appears, will not be rushed.
Yahweh speaks the words of his covenant, the Great Promise Maker renewing what has been said previously. His covenant remains the same - Abram's descendants will be many. There are extra details here - kings will come from you, a royal history to unfold. It is a grand promise, and as a symbol of Abram's future God gives him a new name: Abraham. The covenant is not just with Abraham, father of many, but with all his offspring in all generations. The covenant is everlasting.
The promise of land is also reiterated - Abraham is currently a foreigner in Canaan but it shall belong to his family. Yahweh will be their God.