Commentary for Genesis 6:17

ואני הנני מביא AND I, BEHOLD, I DO BRING — God says, “Now I am prepared to agree with those angels who cautioned Me and long ago said to Me (when I was about to create man), (Psalms 8:5) “What is man that thou art mindful of him” (Genesis Rabbah 31:12).

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.”⁴²Psalms 8:5. Thus the words of Rashi quoting Bereshith Rabbah.⁴³31:15.
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;⁴⁴Leviticus 26:28. The word va’ani (And I) thus intimates the attribute of judgment. so also, I am He! behold, My covenant is with thee;⁴⁵Genesis 17:4. And as for Me, this is My covenant.⁴⁶Isaiah 59:21. 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.⁴⁷Genesis 9:12. — He maketh sore, and He bindeth up.⁴⁸Job 5:18. The learned student [in the mystic lore of the Cabala] will understand.

ואני הנני מביא את המבול, G’d is saying, that Noach’s task is to build the ark, whereas He, when the time expires, will bring on the deluge He had threatened as soon as the ark would be completed. The word מבול is a variant of מפלה, referring to something lost as in Deut. 14,21 כל נבלה, a carcass being a life lost. The definitive article ה in המבול refers to the destruction, the nature of which had not previously been spelled out. [my paraphrasing. Ed.]