John Calvin Commentary Genesis 15:7

"And he said unto him, I am Jehovah that brought thee out of Ur of the Chaldees, to give thee this land to inherit it." — Genesis 15:7 (ASV)

I am the Lord that brought thee. Since it greatly concerns us to have God as the guide of our whole life, so that we may know that we have not rashly entered on some doubtful path, the Lord therefore confirms Abram in the course of his vocation and reminds him of the original benefit of his deliverance. It is as if He had said, ‘I, after I stretched out My hand to you, to lead you out from the labyrinth of death, have extended My favor toward you so far.

You, therefore, respond to Me in turn by constantly advancing; and maintain your faith steadfastly, from the beginning even to the end.’ This is said not only with respect to Abram—so that he, gathering together the promises of God made to him from the very beginning of his life of faith, should form them into one whole—but also so that all the pious may learn to regard the beginning of their vocation as flowing perpetually from Abram, their common father. In this way, they may securely boast with Paul that they know in whom they have believed (2 Timothy 1:12). Furthermore, they may know that God, who in the person of Abram had separated a church for Himself, would be a faithful keeper of the salvation entrusted to Him.

That the Lord declares Himself to have been Abram’s deliverer for this very purpose becomes clear because He connects the promise He is now about to give with the prior redemption. It is as if He were saying, ‘I do not now for the first time begin to promise you this land.

For it was on this account that I brought you out of your own country, to make you the lord and heir of this land. Now therefore I make a covenant with you in the same way; lest you consider yourself to have been deceived or fed with empty words; and I command you to remember the first covenant, so that the new promise, which after many years I now repeat, may be more firmly supported.’