What is the meaning of "Shot la'Sus"?
Rashi: The staff is made for [hitting] a horse.
What is the comparison to Kesilim to a horse and donkey?
Rashi: Afflictions are proper for a Rasha (just like these Kelim are proper for these animals).
Malbim: Animals do not have intellect to conduct themselves. They need a staff and halter. A donkey is more foolish than a horse; it does not understand via a staff, and needs a halter to stop it from straying from the path. Man has intellect and choice so he himself will go on the good path. A Kesil is estranged from the way of Chachmah due to his desire. He is like an animal - its nature conducts it, and not intellect. He needs a staff, like it. The staff and afflictions force him to go in the paved path.
