Ramban

NOW THEREFORE LET ME ALONE, THAT MY WRATH MAY WAX HOT AGAINST THEM. The meaning of this cannot be “let Me alone and I will become angry,” for if His anger had not been aroused yet, why should it wax hot as soon as Moses leaves Him alone? But in line with the plain meaning of Scripture the meaning thereof is: “leave Me, and I will consume them in My burning anger,” similar in thought to the expression, let Me alone, and I will destroy them., Verse 14. By way of the Truth, [the mystic lore of the Cabala], the verse means: “My mercy will subside, and My attribute of justice will wax hot against them and I will consume them with it, for with Me [i.e. when the attribute of mercy is before Me], it has no power over them.” This is the meaning of the expression, And Moses besought the face of the Eternal his G-d, (“face of”) alludes to the attribute of justice (Bachya). being similar in usage to the expression, the face of the Lord Eternal G-d, the G-d of Israel. And so Moses mentioned [in his prayer] in the Book of Deuteronomy, O G-d Eternal — first the name of G-d with Aleph Dalet, which alludes to the attribute of justice. followed by the name of Yod Hei. It is possible that the word vay’chal (and he besought) is of the root t’chilah (beginning). [of the root t’chilah, meaning “beginning” or “first”], because [in the order of the attributes as they are arranged from lowest to highest, the one of justice] is nearest to us” (Ricanti). See also Bachya, in my edition, Vol. II, p. 332. Understand it and you will know.