Ramban — Genesis 6:17

“AND, BEHOLD, I DO BRING THE FLOOD. “Now I agree with those angels who long ago said to Me [when I was about to create man], What is man that Thou art mindful of him.” Thus the words of Rashi quoting Bereshith Rabbah. But I wonder: in what way did He “agree” with them since He left man a remnant for a great deliverance through Noah and his sons and all living things to increase their seed as the sand! Perhaps this agreement with their opinion signified [His intent which was to come to fruition] when He would show them no mercy. [However, when the Divine quality of mercy was introduced, it resulted in the deliverance of mankind through Noah.] By way of the truth [the mystic lore of the Cabala], va’ani (And I) is similar to: And I also will chastise you; (And I) thus intimates the attribute of judgment. so also, I am He! behold, My covenant is with thee; And as for Me, this is My covenant. The verse here thus states: “I also will have My hand on them for having destroyed the earth.” This is why He said [after the flood]: This is the token of the covenant which I make. — He maketh sore, and He bindeth up. The learned student [in the mystic lore of the Cabala] will understand.”