Rashi: One who sends words via a Kesil, he cuts off ¹ the legs of many messengers, to return to fix what the first one made crooked. He drinks Chamas - his friend is angry due to the first messenger.

Malbim: This is how to answer the Kesil. He drinks Chamas - he cuts the legs. What words does he send with the Kesil? His friend is angry due to the first messenger. The verse compares the banquet of desire that the Kesil drinks, i.e. he is drawn after his desire, to one who is drunk from wine, just he drinks Chamas in place of wine. This Chamas cuts off legs. Just like wine cuts off legs of the drunkard - he cannot stand on his legs - so Chamas cuts off legs of the Kesil who drinks it.