Parashas Vaeira · Side page (no TT primary unit)
וָאֵרָ֗א אֶל־אַבְרָהָ֛ם אֶל־יִצְחָ֥ק וְאֶֽל־יַעֲקֹ֖ב בְּאֵ֣ל שַׁדָּ֑י וּשְׁמִ֣י ה׳ לֹ֥א נוֹדַ֖עְתִּי לָהֶֽם׃
And I appeared to Avraham, to Yitzchak, and to Yaakov as El Shaddai, but by My name Hashem I was not known to them.
Shemos Rabbah 6:1 / Sanhedrin 111a parallels — EXTRA.
באל שדי —\ldots הבטחתי ולא קיימתי.
English: “As El Shaddai” — \ldots I promised but had not [yet] fulfilled.
Custom
Chazal read the verse as distinguishing the God of promise from the God of fulfillment now about to act.