Quick answer
The fool's mouth walks him into fights, entering quarrels the way feet enter a room, and escalating until it has practically ordered the beating it receives.
Read both lines
The first line gives the fool's lips a gait: they "enter into contention," as though disputes were doorways the mouth cannot pass without going in. The second line follows the trajectory: his mouth "calls for blows," keeps talking past every off-ramp until someone obliges. The comedy is deliberate, the tragedy real: the fool is his own herald of harm, deaf to how his words sound in the room. Its twin verse (18:7) completes the case: the mouth that calls for blows in public is, privately, a snare closing on its owner's soul.
Related: Proverbs 17:14 · Proverbs 29:9 · Proverbs 26:17
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.