The first verse speaks of the immediate, the others of the remote, results of the "fool's" temper. First, "contention," then "strokes" or blows, then "destruction," and last, "wounds."

A fool's lips enter into contention,.... That is, between others, when he has nothing to do with it; but he must be meddling, and make himself a party in the contention, which is an argument of his folly; he says things which occasion disputes, raise contentions among men, and provoke to wrath and anger. The Septuagint version is, "the lips of a fool lead him to evils": for, as they lead him to contention and strife, the issue of that is confusion and every evil work;
and his mouth calleth for strokes: as he stirs up and encourages contention, so he proceeds to blows, and excites others to them; from words he goes to blows, and, by the ill and provoking language of his mouth, gets many a blow to himself. Jarchi seems to understand it of chastisement, from the hand of God; see Proverbs 26:3.

What mischief bad men do to themselves by their ungoverned tongues!

The quarrelsome bring trouble on themselves. Their rash language ensnares them (Proverbs 6:2).

6 The lips of the fool engage in strife,
And his mouth calleth for stripes.
We may translate: the lips of the fool cause strife, for בּוא ב, to come with anything, e.g., Psalm 66:13, is equivalent to bring it (to bring forward), as also: they engage in strife; as one says בּוא בדמים: to be engaged in bloodshed, 1-Samuel 25:26. We prefer this intrant (ingerunt se), with Schultens and Fleischer. יבאוּ for תּבאנה, a synallage generis, to which, by means of a "self-deception of the language" (Fl.), the apparent masculine ending of such duals may have contributed. The stripes which the fool calleth for (קרא ל, like Proverbs 2:3) are such as he himself carries off, for it comes a verbis ad verbera. The lxx: his bold mouth calleth for death (פיו ההמה מות יקרא); למהלמות has, in codd. and old editions, the Mem raphatum, as also at 19:29; the sing. is thus מהלוּם, like מנוּל to מנעליו, for the Mem dagessatum is to be expected in the inflected מהלם, by the passing over of the ō into ǔ.