Were David’s enemies likely to follow his advice, tremble before God, offer sacrifices for their sin and begin to trust the Almighty? It was not very likely! It is not even likely that David spoke these words to them. They are part of the psalm, words that David spoke to God and would have liked to have spoken to his enemies but probably did not have the chance to utter. But here is the important thing: although his enemies did not come to trust God, David did. He had trusted God in the past. He had laid his grief over the false accusations of his enemies before him. Now God provided the peace he was seeking. There were three things God provided.
First, God assured him of his favor (v. 6). In their distress the people around David were asking, “Who can show us any good?” In their opinion, there was nothing good about their circumstances at all. But God brought to David’s mind the well-known Aaronic blessing of Numbers 6:24-26: “The Lord bless you and keep you; the Lord make his face shine upon you and be gracious to you; the Lord turn his face toward you and give you peace.” He remembers it in an abbreviated form in verse 6. Thus, he was reminded that the one who had shown him good in the past can be counted on to show him good again, even God himself.
Second, God filled him with joy, greater than the joy of those reaping an abundant harvest (v. 7). Joy floods our hearts when we are conscious of the Lord’s favor.
Finally, God gave David peace even in the turmoil (v. 8). This is the final blessing that came to David as he tried to help those who were his enemies. As Craigie says, “At the end, the psalmist has seen that he is better off than his adversaries. He has advised them to lie still on their beds, in an attempt to curtail their evil (v. 5), but he could lie on his bed and sleep the sleep of peace which came from God.”8 It is always that way. If we leave our problems with God, he will shoulder them. And he will enable us to sleep in peace.
8Peter C. Craigie, Word Biblical Commentary, vol. 19, Psalms 1-50 (Waco, TX: Word, 1983) p. 82.