Psalm 38:4 For my iniquities have gone over my head; like a heavy burden, they are too heavy for me.
David had sinned, and he felt the conviction of the Spirit inside of him! David knew that he had to confess what he had done, for it was too heavy for him to bear. We do not have to bear our sin! Jesus has already paid it all on the cross. Our slates have been wiped clean from our transgressions.
Isaiah 53:5 But he was pierced for our transgressions; he was crushed for our iniquities; upon him was the chastisement that brought us peace, and with his wounds we are healed.