1 See, a king will reign in righteousness and rulers will rule with justice.
2 Each one will be like a shelter from the wind and a refuge from the storm, like streams of water in the desert and the shadow of a great rock in a thirsty land.
3 Then the eyes of those who see will no longer be closed, and the ears of those who hear will listen.
4 The fearful [or rash] heart will know and understand, and the stammering tongue will be fluent and clear.
5 No longer will the fool be called noble nor the scoundrel be highly respected.
6 For fools speak folly, their hearts are bent on evil: They practice ungodliness and spread error concerning the Lord; the hungry they leave empty and from the thirsty they withhold water.
In this chapter the first eight verses are about the Kingdom of Righteousness and the following twelve verses are about The Women of Jerusalem. Our focus is on the Kingdom of Righteousness where we have two verses, four and six, that speak to the heart condition.
The first case in verse four speaks of a fearful or rash (always hurried) heart so fearful or hurried it never really knows or understand, but now with a king reigning in righteousness it will no longer be fearful or hurried and the heart will know and understand. The king who reigns in righteousness was initially true of king Hezekiah, but verses three and four reveal a time which would be much more applicable to the return of Christ. The Benson Commentary tells us the verses
relate to happier times than Hezekiah lived to see. And therefore we may justly say, “That the reformation which Hezekiah made was but a shadow of those greater improvements in grace and holiness, which properly belong to the times of the gospel. — Lowth.
Then we come to verses five and six; especially verse six and its reference to the hearts of fools being bent on evil. An individual who speaks folly is a person who is acting in conflict with God’s will as he always chooses his own way instead of God’s way. Such a person under an ungodly king could be praised for doing it their own way and even given an office of great power. However, under a Godly and honorable king they would hold no office for they would be seen for what and who they are. Their ungodliness, lying about God, and selfishness concerning others would be exposed as it says in the last part of verse six:
They practice ungodliness and spread error concerning the Lord; the hungry they leave empty and from the thirsty they withhold water.
We can only look forward to such leadership in our own time. At the same time we wait patiently for the return of Jesus when we will have reason for great rejoicing.