Isaiah 32:4
The heart also of the rash shall understand knowledge, and the tongue of the stammerers shall be ready to speak plainly. The heart also of the rash shall understand knowledge, and the tongue of the stammerers shall be ready to speak plainly.
Under the righteous King, those who are rash come to understand knowledge, and those whose speech falters learn to speak plainly. This transformation takes place where truth and falsehood are distinguished without confusion. In that same setting the deceit of the vile is laid bare, while the generous are recognized by the good they practice.
When God renews and empowers his people, he supplies understanding to those who lack it and gives hesitant speakers power to speak clearly. By that renewal the timid are made courageous witnesses, so that many voices join in proclaiming the truths of his word. True piety, close connection with God, and a daily living knowledge of Christ make even a stammering tongue eloquent and ready to speak plainly.