וְנִקֵּ֖יתִי דָּמָ֣ם לֹֽא־נִקֵּ֑יתִי וַֽיהוָ֖ה שֹׁכֵ֥ן בְּצִיּֽוֹן׃
And I will hold as innocent their blood that I have not held as innocent; And the LORD dwelleth in Zion.
Rashi on Joel
Now should I cleanse, their blood I will not cleanse—Even if I cleanse them of other sins in their hands, and of the evils they have done to Me, I will not cleanse them of the blood of the children of Judah. When will this come to pass? At the time the Holy One, blessed be He, dwells in Zion.