What is the significance of "Tov Erech Apayim mi'Gibor"?
Avos (4:1): A Gibor is one who conquers his Yetzer.
R. Yonah: He does take vengeance when someone sins against him, until he resolves with his Sechel what is proper to do to him. At the time of the sin, his anger burns in him. He will not decide what is proper, and will not be saved from transgression. His anger closer his eyes and his Sechel - u'Va'al Chemah Rav Pesha" (29:22). Another benefit of delaying anger - he can wait until he has the ability to take vengeance. This is better than a Gibor. Strength of the heart and Da'as over desire is better than strength of the limbs.
Orchos Tzadikim (Sha'ar ha'Ka'as DH Af Al Pi and DH v'Da): It is one who has the Midah of anger, and overpowers it and acts as if he does not have it.
Malbim: A Gibor who does not delay anger, and immediately takes vengeance from his enemies, he shows his strength via overpowering his external enemy. However, if he heeds the laws of Chachmah not to take vengeance, and overpowers the Yetzarim of envy and vengeance, which command the limbs to take vengeance, he is better than a Gibor. He overpowered his internal enemy, which is stronger. One can have Erech Apayim, but he is Ketzar Ru'ach. Even though he does not do an act of vengeance, the Ru'ach puts images of vengeance on his heart, and bears hatred - "u'Ketzar Ru'ach Merim Iveles" (14:29).
Who is "Moshel b'Rucho"?
Rashi: It is one who conquers his Yetzer.
R. Yonah #1: He rules to delay his anger, until he resolves what is proper to do. "Rucho" is anger, like "Kol Rucho Yotzi Chesil" (29:11).
R. Yonah #2: He rules over his desire - the Nefesh that desires, to guard it from every sin and lowly Midah. Also "Shamah ha'Ru'ach Laleches" (Yechezkel 1:20) refers to Ratzon.
Malbim: This is one who subdues his [internal] enemies not to put images of vengeance on his heart at all.
Why is "Moshel b'Rucho" better than one who conquers a city?
R. Yonah: He rules over his anger to remove it, and not take vengeance. This is better than Erech Apayim, therefore it says he is better than one who conquers a city - a higher level than Gibor.
Malbim: The Ru'ach is like a fortified city full of a great army of the old, foolish Yetzer - images of the Ru'ach for all bad Midos. If he overpowers the Ru'ach, he conquered the entire small city. This is greater Gevurah than conquering an external city with an army and strength!
