Midrash sobre II Samuel 22:28

Ula said: "Jerusalem will not be redeemed except through charity," as it is said (Is. 1, 27) Zion shall be redeemed through justice, and her converts through Tzedakah (righteousness, or charity)." R. Papa said: "When the haughty shall cease to exist in Israel, then the magicians [among the Persians] shall cease, as it is said, (Ib. ib. 25) And purge away as with lye thy dross, and remove all thy tin. When the judges [of Israel] shall cease to be, the brutal executions of the Persian court-servants will cease, as it is said (Zeph. 3, 15) The Lord hath removed Mishpatecha (thy judges); He hath cleared away the enemy." R. Jochanan said: "When you see a generation in which wisdom decreases continually, you may hope for the Messiah, as it is said (II Sam. 22, 28) And the afflicted people thou wilt save." R. Jochanan said again: "If you see a generation in which chastisements and evils increase like the waters of the ocean increase, await the Messiah, as it is said (Isa. 59, 19) For there shall come distress like a stream." And thereafter is written, "But unto Zion shall come the redeemer." R. Jochanan said further: "Ben David will appear either in a generation in which all will be righteous, or in one in which all will be wicked. All righteous, as it is said, (Ib. 60, 21) And thy people — they all will be righteous, forever shall they possess the land. Or all wicked, as it is said (Ib. 59, 16) "And he saw that there was no man, and wondered that there was no intercessor." And it is also written (Ib. 48, 11) For My own sake, for My own sake, will I do it."