Cease from anger, and forsake wrath: {g} fret not thyself in any wise to do evil.

(g) Meaning, unless he moderates his affection, he will be led to do as they do.

Wesley's Notes

37:8 Fret not - Either against the sinner for his success; or against God. Do evil - If grief arise in thee, take care that it do not transport thee to sin.

Matthew Henry's Concise Commentary

37:7-20 Let us be satisfied that God will make all to work for good to us. Let us not discompose ourselves at what we see in this world. A fretful, discontented spirit is open to many temptations. For, in all respects, the little which is allotted to the righteous, is more comfortable and more profitable than the ill-gotten and abused riches of ungodly men. It comes from a hand of special love. God provides plentifully and well, not only for his working servants, but for his waiting servants. They have that which is better than wealth, peace of mind, peace with God, and then peace in God; that peace which the world cannot give, and which the world cannot have. God knows the believer's days. Not one day's work shall go unrewarded. Their time on earth is reckoned by days, which will soon be numbered; but heavenly happiness shall be for ever. This will be a real support to believers in evil times. Those that rest on the Rock of ages, have no reason to envy the wicked the support of their broken reeds.