Thomas Brooks emphasizes the folly of fretting against God during times of distress, illustrating how individuals often blame God for their suffering instead of recognizing their own sins that lead to misery. He cites examples from scripture, such as Pharaoh's defiance and Jonah's misplaced anger, to show that a fretful heart can lead to a direct challenge against God. Brooks warns that fretting only brings more suffering and that true wisdom lies in accepting God's will rather than rebelling against it. He encourages believers to refrain from anger towards God and to seek understanding in their trials.