Midrash su Deuteronomio 23:6

"When a person incurs guilt accidentally by [transgressing one among] all of the commandments of YHVH": This is that of which the Bible says: "And indeed I have witnessed under the sun the place of judgment..." (Ecclesiastes 3:16). Rabbi Eliezer and Rabbi Joshua [in conversation]...

Haman wanted to destroy all the Jews, but the Holy One, blessed be He, did not desire it, and therefore: Whereas it was turned to the contrary, that the Jews ruled over them that hated them (Est. 9:1). Balaam and Balak wanted to curse Israel, but the Holy One, blessed be He, did not agree, as it is said: Nevertheless, the Lord thy God will not hearken unto Balaam (Deut. 23:6). Hence it is said: Who is he that saith, and it came to pass, when the Lord commandeth it not? (Lam. 3:37). Hadrian said to R. Joshua: “Mighty is the lamb that can survive among seventy wolves.” And he replied: “Mighty is the shepherd who can save and protect the lamb, and destroy the wolves surrounding her.” Therefore, it is written: No weapon that is formed against thee shall prosper (Ps. 54:17).

(Ib. 23, 16) And put a word in his mouth. R. Jochanan said: From the blessings of that wicked you may learn what he intended to say, [should he not have been prevented]. He wanted to say: That Israel shall not possess any houses of prayer and of learning, [but he was compelled to say] (Ib. 24, 5) How goodly are thy tents, O Jacob. He intended to say that the Shechina shall not rest upon them, [and said] Thy dwellings, O Israel. [He intended to say] that their kingdoms shall not be prolonged, and said, As streams are they spread forth. [He intended to say] that they shall not possess olives and vineyards, [and said,] As gardens by the river's side. They shall have a bad odor, and said, As aloes which the Lord had planted. They shall not have kings of nice appearance, and said, And cedar-trees beside the water. Their kings shall not be descendants of kings, and said, Water runneth out of His buckets. Their kingdom shall not rule over other nations, and said, That his seed may be moistened by abundance of waters. Their kingdom shall not be strong enough, and said, And his king shall be higher than Agag. And their kingdom shall not be feared, and said, And raised on high shall be his kingdom." R. Abba b. Chana said: "All Bil'am's blessings were curses except concerning houses of prayer and of learning, as it is said (Deut. 23, 6) And the Lord thy God has changed unto thee the curse into a blessing, because the Lord thy God loved thee. It reads curse, singular, but not curses, plural."