Bava Basra 9b: A covert gift of Tzedakah suppresses damaging angels of anger more than the prayer of Moshe Rabeinu! Moshe said "Ki Yagorti Mipnei ha'Af veha'Chemah" (he feared them). Covert Tzedakah covers them ¹ . Rashi - also "v'Shochad ba'Cheik" is [covert] Tzedakah.

R. Yonah: If one does not investigate and seek Aniyim, his sin is not so great. It is great if he refuses to give to an Oni who calls to him. However, it is proper to pursue Tzedakah and investigate needs of Aniyim and "Maskil El Dal" (Tehilim 41:2). He will acquire awesome reward. Even if he sins, the merit of a covert gift will cover anger ² . Giving covertly spares the Oni from shame. The giver should not glorify himself for giving. One should not give for grandeur, rather, to serve Hashem. Chazal said that the greatest Tzedakah, which saves from death, is when he does not know to whom he gives, and the Oni does not know from whom he receives (Bava Basra 10b).

Malbim: Money given covertly is sometimes good, and sometimes bad. Matan implies something not given for a matter, e.g. what one gives to an Oni, or gifts given to officers and Ashirim. Gifts of Tzedakah suppress anger above. Also refer to 21:14:2:3.

Bava Basra 9b: Any judge who takes bribery brings harsh Chemah to the world.

R. Yonah: Also when a man is afflicted - a decree was made due to his sins - covert Tzedakah will cover harsh anger. Tzedakah given at a time of affliction is called Shochad, for he gives a 'bribe' at a time of fear and affliction to redeem his Nefesh from it. Chemah is harsher than Af.

Malbim: A gift to a judge or officer suppresses anger below, but the money given covertly to make the judgment crooked and tilt the verdict, this is called Shochad, which is given to the ba'Cheik (lap) of the judge. This arouses fierce anger above, or [also] below, if the king finds out.