NOTES for Gen 17:1-27
Of the several encounters between Abraham and God mentioned in the Book of Genesis, only two are described in detail. The second tells how Abraham and Sarah receive new names and how God begins to act: it is during this second encounter that He tells Abraham that a son will be born to him in a year's time. At last, God directly enters his life and the life of his family. The birth of a son is understandable, for 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 was true of circumcision, also mentioned here in the account of the second of Abraham's theophanies to be described in detail in Genesis.
Many biblical scholars believe that the account of circumcision is a late insertion into the text, resulting from the fact that the ancient tradition, once written down, passed through the hands of editors from priestly circles. Some concepts characteristic of those circles can indeed be found in the description of the second theophany. Yet even if the account of circumcision was added to the ancient tradition later, it proved remarkably appropriate, because circumcision really had been an initiatory rite from very early times. At first it was used in coming-of-age initiations, and later in religious ones. In Abraham's time circumcision was most likely understood, both by Abraham himself and by his fellow 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 and new, while the former, old person disappears and yields his place to the new one. It is no accident that God calls Himself by the name El Shaddai, "God of power" (this name is usually translated so that El Shaddai becomes "God Almighty"). This refers to the power that everyone in antiquity revered, because it sustains the world, and without it no life or indeed any existence is possible.
Gods, spirits, and human beings could all be bearers of this power, but not its source. By calling Himself El Shaddai, the God of power, the God of Abraham is saying precisely this. He points to Himself as the source of the power by which the world is sustained, the power that transforms Abraham and Sarah themselves, making them different people who bear new names. This is what spiritual formation is: it is impossible without inner change, and impossible without an encounter with God as well.