Matthew Poole and continuators on Isaiah 32:4

4. The heart also of the rash shall understand knowledge , and the tongue of the stammerers shall be ready to speak plainly.

Who were hasty and heady in judging of Things; which is an Argument of Ignorance and Folly.

Shall become more knowing and considerate in their Judgments and Actions.

That used to speak of the Things of God, darkly, and doubtfully, and unwillingly. As Men's Understandings shall then be enlightned, so their Speech shall be reformed. Which though it was in part fulfilled in Hezekiah; this Reformation being effected in some measure by his Counsel and Example, and by the powerful Preaching of the Levites, whom he excited and encouraged to Teach the good knowledge of the Lord, as is said, 2 Chron. 30. 22. yet was truly and fully accomplished onely by Christ, who wrought this wonderful Change in an innumerable company both of Iews and Gentiles.

Marginal references: Heb. hasty.; Or, elegantly.