NOTES for Gen 17:1-27
Of the several meetings between Abraham and God mentioned in Genesis, only two are described in detail. The second of them is about Abraham and Sarah receiving new names, and about God beginning to act: it is during this second meeting that He tells Abraham that a son will be born to him in a year. God finally enters directly into his life and into the life of his family. The birth of a son is understandable, since it had been promised to Abraham earlier. But what does the change of name mean? In antiquity such a change, if not always, then very often had a dedicatory, initiatory meaning. The same is true of circumcision, mentioned here as well in the story of the second theophany to Abraham described in detail in Genesis.
Many biblical scholars think that the account of circumcision is a late insertion into the text, the result of an ancient tradition, once written down, passing through the hands of editors from a priestly milieu. Some concepts characteristic of that milieu can indeed be found in the description of the second theophany, but still the account of circumcision, even if it was added to the ancient tradition later, proved surprisingly appropriate: circumcision really had been an initiatory rite from very early times. At first these were age-related initiations, and later religious ones as well. Most of all, circumcision in Abraham's time was indeed understood by him and by his tribesmen as a sign of a kind of dedication to God.
Circumcision alone was not enough. A change of name presupposes that the person himself changes, that he becomes different, new, while the former, old person disappears and gives way to the new. And it is no accident that God calls Himself by the name El Shaddai, "God of strength" (usually this name is translated so that El Shaddai becomes "God Almighty"). The point is the strength that all people in antiquity revered, because the world is upheld by it and without it no life, and no existence at all, is possible.
Gods, spirits, and human beings could be bearers of this strength, but not its source. When Abraham's God calls Himself El Shaddai, God of strength, He is speaking precisely of this. He points to Himself as the source of the strength by which the world is upheld. It is the strength that changes Abraham and Sarah themselves, making them different people who bear new names. This is spiritual formation: it is impossible without inward change, and also without a meeting with God.