One of the most difficult questions when we sing about Christ in the Psalms, cf. Luke 24:44, is “What about the confessions of sin in the Psalms? Jesus never sinned!”
For some examples, how do verses like these apply to Jesus?
• I acknowledged by sin to you, and I did not cover my iniquity; I said, ‘I will confess my transgressions to the Lord’, and you forgave the iniquity of my sin. (Psalm 32:5)
• Wash me thoroughly from my iniquity, and cleanse me from my sin. For I know my transgressions, and my sin is ever before me. (Psalm 51:2,3)
• I have gone away like a lost sheep… (Psalm 119:176)
Never forget that Jesus never sinned. He had no personal iniquity or transgressions to confess. He never went astray like a lost sheep. Jesus was obedient - and completely obedient - even to the death of the cross, cf. Philippians. 2:9. If Jesus had sinned we would not have a Savior; and because Jesus was perfectly obedient in Him we have a perfect righteousness. Without this we wouldn’t have the good news of the Gospel.
So how can we sing about Jesus in Psalms that confess sin?
The first thing to keep in mind is that the Psalms were written by human authors who did sin, who needed to confess their sin, and who had to receive forgiveness of sins. This reminds us that while the Psalms show us the sinless Jesus, they were written by people who were not sinless. We can (and should) relate to that as we - who also are not sinless - use the Psalms for our own devotions and as a pattern for godliness.
At the same time, we need to take with the deepest seriousness the profound truth that Jesus, who knew no sin by personal commission, nevertheless became sin (but NOT “a sinner”) for His people: For our sake, he, i.e. God the Father, made him, i.e. Jesus, to be sin who knew no sin, so that in him we might become the righteousness of God. (II Corinthians 5:21).
That means that Jesus:
• Felt in his inmost being what it meant to be a sinner who was under the wrath of God. He was, in the fullest sense of the word, a man of sorrows and acquainted with grief (Isaiah 53:3).
• Experienced to the greatest depths possible the power of sin that makes our bones waste away through our groaning all the day and that dries up our strength as in the heat of summer, because God’s hand is heavy on us, cf. Psalm 32:3.4.
• Knew in ways no mere mortal could ever even begin to grasp what it meant that sin causes us to be forsaken of everything but the eternal justice of an offended God. What awesome sorrow there is in Jesus’ cry, My God. My God. Why have you forsaken me? (Psalm 22:1)
So, as you sing what are often called “The Penitential Psalms”, e.g. Psalms 32, 51, 130, 143, remember that Christ experienced the depths of sin’s curse when he became a curse for us, cf. Galatians 3:13 - all so that the curse of sin might be taken away from those who trust in Jesus Christ as their sin-bearer. And he went to those depths because of the depths of his love for you! May that cause you to confess your own sins and receive from Jesus the forgiveness that comes at such a great price - the price of the sinless one becoming sin for us.