The theme of Psalms 36 and 37 is "trust in God." In Psalm 36, what the wicked man is and does is contrasted with what the Lord is and does. The Lord is to be petitioned and trusted.
Psalm 37 is one of the best-loved of all the Psalms. Verse 4 is one of my key verses in the Old Testament. "Delight thyself also in the Lord; and He shall give thee the desires of thine heart." This Psalm tells of God's provision for His children. He also promises us His protection and His peace. He tells us that He will give us the desires of our heart if we will delight ourselves in Him. When I first read that verse many years ago I could not believe it could be true. Could God possibly give me the desires of my heart? The answer is--YES! If I meet His conditions; if I delight myself in Him. The word "delight" means "to fall in love with." If I am willing to fall in love with the Lord Jesus, and abandon my will to His will in every matter; there is no end to the desires He will give me.
David always seems to be puzzled by the prevalence of wickedness; and in Psalm 37 he gives his philosophy as to how to live in the midst of wicked people--do good, trust God, and don't worry!
Psalm 38 is a Psalm of bitter anguish, another of the Penitential Psalms. David seemed to be suffering from some loathsome disease, caused by his sin. Because of it, his closest friends and nearest relatives had become estranged, and enemies had multiplied and become very bold. This Psalm shows how the "man after God's own heart" sometimes went to the depths in sorrow and humiliation for his sin.
