Numbers 23:8

מה אקב ולא קבה אל HOW SHALL I CURSE WHOM GOD HATH NOT CURSED — Even when they deserved to be cursed, they were not cursed. When their ancestor, Jacob, made mention of their sin — (Genesis 49:6) “For in their anger they slew a man” — he cursed their anger only, as it is said, (Genesis 49:7) “Cursed be their anger”. When their ancestor, Jacob, went to his father with deceit he deserved to be cursed, but what is stated there (Genesis 27:33)? “Yea, he shall be blessed”. In the case of those tribes who had to recite the blessings it is said, (Deuteronomy 27:12) “These shall stand to bless the people”, but in the case of those who had to pronounce the curses it does not state, “And these shall stand to curse the people”, but, “And these shall stand for the curse”, — it does not wish to mention the term “cursing” in direct reference to them (the people) (Midrash Tanchuma, Vayechi 1; Midrash Tanchuma, Balak 12). לא זעם ה׳” GOD IS NOT ANGRY — As for me, my power lies only in that I know to determine the exact moment when the Holy One, blessed be He, is angry, and He has not been angry all these days that I have been coming to you. And this is the meaning of what is said (Micah 6:5): “O my people, remember now what [Balak, king of Moab] devised and what Balaam [the son of Beor] answered him … that ye may know the righteous acts of the Lord” (Sanhedrin 105b).

מָ֣ה אֶקֹּ֔ב לֹ֥א קַבֹּ֖ה אֵ֑ל וּמָ֣ה אֶזְעֹ֔ם לֹ֥א זָעַ֖ם יְהֹוָֽה׃

How shall I curse, whom God has not cursed? or how shall I denounce whom the Lord has not denounced?