1)
Why is it pleasant for those who rebuke?
1.
Tamid 28a: The proper path one should choose is to love (Maharsha - giving) rebuke. Pleasantness, good and blessing come to the world when there is rebuke.
2.
Malbim: They rebuke them, and do not flatter them. The good path is pleasant for the Nefesh. Additionally, they get a Brachah, and not the curse of the flatterers.
