Charles H. Spurgeon on Psalms 37:8

Cease from anger and forsake wrath. Especially anger against the arrangements of Providence, and jealousies of the temporary pleasures of those who are so soon to be banished from all comfort. Anger anywhere is madness, here it is aggravate insanity. Yet since anger will try to keep us company, we must resolvedly forsake it. Fret not thyself in any wise to do evil. By no reasonings and under no circumstances be led into such a course. Fretfulness lies upon the verge of great sin. Many who have indulged a murmuring disposition have at last come to sin, in order to gain their fancied rights. Beware of carping at others, study to be yourself found in the right way; and as you would dread outward sin, tremble at inward repining.