ספר שיחות מוהר"ן אות - רפט

I heard in his name: that the great Tzadik — in the word he speaks, all the words necessary for all of Israel are included, and everything that every single person of Israel needs. And this is (Devarim 1:1): "These are the words which Moshe spoke to all of Israel" — that the words Moshe spoke became words to all of Israel. For each and every person of Israel found within them what he needed, as mentioned above.