Hashem says to Moshe Rabeinu, “Tell the Yidden, my name is “Eh-yeh asher Eh-yeh” - I will be with them during this golus, and I will be with them during future goluyos. And Moshe complained “Why mention future problems. Enough to deal with those when they arrive.” And Hashem agreed, “Just tell them “Eh-yeh sent me.”
The sforim hakdoshim (I think from the Chozeh of Lublin) say that “Eh-yeh” (I will be) is a holy name associated with doing teshuva. i.e. regardless of my past deeds, Eh-yeh - from now on I will be good. Based on that, I think we can say (and perhaps it was already said) that at first Hashem said Eh-yeh asher Eh-yeh - true Teshuva is when a person takes upon himself “I will be good now and I will be good always”. But Moshe the faithful shepherd interceded and said, “Why overwhelm them about being good for long periods of time? It would work better if they concern themselves only with being good for a day at a time.” And, lo and behold, Hashem agreed and said, “Okay, tell them ‘Eh-yeh’ is the way to go - I will be good today - I will overcome this nisayon”. A day at a time - a nisayon at a time.