If you’re struggling with sin…

This verse is a way for us to strive to leave our past sins behind us. The psalmist here, David, is asking for a pardoning of his sins from God. He is asking God to forget what he is unable to forget because in order for us to strive for a life separate from sin, we must recognize that Satan is cunning and very good at recycling previous sins. And let's also remember that we are able to ask things like this because of God's goodness and mercy, not our merit or works. We are to come to God knowing our unworthiness and inability to escape sin without Him. That shows humility and faith in God.