Keil & Delitzsch, on Gen 17:4

“And God said to him: I AM, and my covenant is with thee, and thou shalt be a father of many nations.”

“On the part of God אני placed at the beginning absolutely: so far as I am concerned, for my part) it was to consist of this: (1) that God would make Abram the father (אב instead of אני chosen with reference to the name Abram) of a multitude of nations, the ancestor of nations and kings; (2) that He would be God, show Himself to be God, in an eternal covenant relation, to him and to his posterity, according to their families, according to all their successive generations; and (3) that He would give them the land in which he had wandered as a foreigner, viz., all Canaan, for an everlasting possession. As a pledge of this promise God changed his name אברם, i.e., high father, into אברהם, i.e., father of the multitude, from אב and רהם, Arab. ruhâm = multitude. In this name God gave him a tangible pledge of the fulfilment of His covenant, inasmuch as a name which God gives cannot be a mere empty sound, but must be the expression of something real, or eventually acquire reality.”

Imported from an open dataset — not yet checked against the printed edition.