What is the meaning of "Gedal Chemah Nosei Onesh [Ki Im Tatzil v'Od Tosif]"?
Rashi: If you will pass over your anger and save your hater, if you see evil coming to him, you will increase days and good.
R. Yonah: Even though verse 18 warned not to have mercy to his crying, if you are full of anger, you will be punished if you strike him more than is proper. You will bear sin, just like you would be punished for [striking] a stranger.
Malbim #1: The punishment bears growth of anger. If he increases anger, this will bear punishment; via the punishment that he gives to him, his anger is assuaged.
Malbim #2: If a child grows up on Chemah (with an Aleph, i.e. butter,) like "bi'Rchotz Halichai b'Chemah" (Iyov 29:6), the fruit of this upbringing will be punishment. If you will save and remove the punishment, it will yield more fruits, and the punishment will be greater.
Why does it say "Ki Im Tatzil v'Od Tosif"?
R. Yonah: So is proper for you to do, to save him from your hand at the time of your anger, lest you strike him a great blow more than is proper. You will strike him more after your anger passes. "Ki Im" [means rather,] like "Ki Im Ko Sa'asu Lahem" (Devarim 7:5).
Malbim: If you will save and not punish him, the anger will increase.
