Old names do not drop off quietly. When the Lord tells Abraham that Abram will no longer be his name, He is rewriting a biography that has already lasted ninety-nine years. Targum Pseudo-Jonathan on Genesis 17:5 renders the change with the traditional etymology: Abraham — av hamon, father of a multitude — because to be the father of a great multitude of peoples have I appointed thee.
The new name holds the old one inside it. Abram was a private identity — exalted father, perhaps, or my father is exalted. Abraham is a public commission. The first name looks back toward his own lineage. The second name looks forward, across the centuries, to nations not yet born.
Ancient readers noticed that in Hebrew the change is one letter — the soft breath of a heh added into the middle of his name. The same letter, the tradition says, that God breathes into creation in the opening verses of Genesis. A single letter of divine breath, slipped into a man's name, turns him from a private self into the ancestor of assemblies and kings.
The Maggid hears something startling here. God can change a person's destiny without replacing the person. Abraham is still Abraham. His memory of the furnace is intact. His marriage to Sarah is intact. His grief over childlessness is still real. What changes is the scope — the same life is now carrying a crowd on its shoulders (Genesis 17:5). Renaming, in the Torah, is not erasure. It is inflation. A life made larger by a breath.