“forgives your every iniquity.” In Psalm 103:3-5 the psalmist is speaking to himself. Thus, the “your” or “you” in those verses do not refer to everyone, but to the psalmist himself, who in this case is King David who penned the psalm. The opening two verses, Psalm 103:1-2, show this, saying, “Bless Yahweh, O my soul.” Leslie Allen (The Word Biblical Commentary) correctly catches the sense of the Hebrew and translates it, “Bless Yahweh, I tell myself...Bless Yahweh, I tell myself.” Another way we know that the psalmist, David, is speaking to himself is that the “you” and “your” are singular in the Hebrew text. If the psalm was addressing the people of God in general, then the “you” and “your” would be plural.
What is happening in Psalm 103 is that we readers are getting a look into the “self-talk” going on inside David’s head, and David is setting a good example for us about how we should talk to ourselves and remind ourselves of all the great things God has done for us. David had plenty of trouble, including trouble he made for himself by his bad decisions. Yet here he is talking to himself and reminding himself of the goodness of God. We can almost hear him lecturing himself and saying, “Now David, bless Yahweh because he forgives your sins, heals your sicknesses, and gets you out of mortal danger.” Wise Christians learn to imitate David and develop positive self-talk that results in a thankful heart and good attitude.
So Psalm 103 gives us a good example of how a person after God’s own heart talks to themself so that they become thankful and praise God. But more than that, we also know that the things God did for David He will do for anyone who loves Him and makes an effort to live a godly life, so we can rely on the fact that God will forgive us, heal us, and deliver us from danger, including “the pit,” Sheol itself. Life is difficult, but we will be a lot better off personally if we learn to be thankful and maintain a positive attitude.