"Behold, he who has repented of his sins, the same is forgiven, and I, the Lord, remember them no more. By this ye may know if a man repenteth of his sins — behold, he will confess them and forsake them."
— Doctrine & Covenants 58:42-43
Christ made an atonement for us - he suffered for our sins in the garden of Gethsemane, he died for us on the hill called Calvary, then he was resurrected so that we might all live again.
The Lord has said that no unclean thing can enter into the kingdom of God. We must be washed clean through the blood of Jesus Christ. How exactly do we do this? In addition to having faith in Christ, and being baptized, we must also repent of our sins. The verse above gives us the key to repentance — we must confess and forsake our sins.
Confession is a powerful exercise in humility. To fall on our knees and confess to God our sins requires us to admit that we are not perfect, that we make mistakes, that we are not always right and we know it. We have to accept the fact that we aren't going anywhere in our progression towards salvation without Christ's atonement - His grace and mercy - to bring us into God's presence. We must confess our wrongdoings and sincerely ask for God's forgiveness so we can be cleansed through the blood of the Lamb.
Forsaking our sins can be very difficult. After acknowledging what we did is wrong, we have to master ourselves — our tempers, our habits, our tongues, our thoughts — to overcome our sins. Again, this can only truly be done through Christ's grace and mercy. Forsaking our sins requires daily (or even hourly!) prayer, asking for God's strength and love to overcome our natural man.
"For the natural man is an enemy to God, and has been from the fall of Adam, and will be, forever and ever, unless he yields to the enticings of the Holy Spirit, and putteth off the natural man and becometh a saint through the atonement of Christ the Lord, and becometh as a child, submissive, meek, humble, patient, full of love, willing to submit to all things which the Lord seeth fit to inflict upon him, even as a child doth submit to his father."
— Mosiah 3:19
When we are patient, humble, and meek, we can truly repent of our sins and become more like Christ. We can become clean through the blood of the Lamb and be worthy to enter His presence.