The Holy One explains something astonishing to Moses. Targum Pseudo-Jonathan preserves the distinction between the revelations: I was revealed unto Abraham, and to Izhak, and to Jakob, as EI-Shaddai; but My Name Ye-ya, as it discovereth My Glory, was not known to them.
Track the theology carefully. Abraham, Isaac, and Jakob — the three patriarchs — knew God as El-Shaddai, the God of covenantal promise, the God who makes barren women fertile and wanderers into nations. But the four-letter Name — YHVH, which the Targum writes defensively as Ye-ya — was withheld from them.
Why Moses Gets the Deeper Name
The sages of the Targumic tradition take pains to explain the progression. El-Shaddai is the Name of private providence — the God who tends each patriarch as a shepherd tends a single sheep. YHVH is the Name of historical action — the God who liberates nations and splits seas.
The Aramaic gloss as it discovereth My Glory is key. The Targum renders it as in the face of My Shekinah. The Name YHVH reveals the Shekinah — the indwelling Presence — in a way that El-Shaddai does not. The patriarchs received promises; Moses receives the Name that makes those promises move.
This is not a demotion of the patriarchs. It is a recognition that every generation gets the Name it can bear. Abraham could not have endured the YHVH revelation; he received the Name suited to his role as covenant-ancestor. Moses can endure it because his role requires a more public divine disclosure.
The takeaway: the Jewish imagination sees revelation as progressive. Each generation receives as much of the divine Name as its history demands. The Exodus requires a Name that can crack an empire, and that Name has been reserved — until now — for the generation that will see it enacted. Moses is about to learn words that Abraham would have struggled to hear.