God moves in our moving. Once our will is set in motion we can expect the power of God to assist us. Even though we may slip and fall in this pursuit of forsaking sin, the blood of Christ is still effective to cleanse us.
Ps 37:24 Though he fall, he shall not be utterly cast down; For the LORD upholds him with His hand.
God fully understands our flesh, and our propensity towards sin, so He has made provision for this in the New Covenant.
1 John 1:9 If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.
The blood of Christ is not just effective when we first come to Christ and receive salvation. We will need it many times throughout our Christian life. Even though we may feel disappointed with ourselves we are not to run from God when we fall, but run to Him.
When He attempted to wash Peter’s feet, Jesus told Peter that although he was completely washed He still needed to wash his hands and feet. The picture Jesus was creating for the disciples refers to the Roman public baths. People would wash in the public baths and then return home. On the way however, their feet and their hands would become dirty again. So, arriving at home they wash their hands and feet. This is the Christian walk. We first meet Christ and He washes us completely clean. We receive salvation and acceptance into the family of God. As we travel through our lives though, there will be times when we offend God (1 John 1:8). At these points we must repent, confess, and turn from our offences again. We are promised the blood of Jesus will cleanse us again so that sin and all the curses that come with it will not stick to our lives (1 John 1:9). This is the great work of the cross. God, through grace has provided a means for regular cleansing, and renewing of our relationship with the Lord.
Thus the power of the Cross is manifested in our life. Repentance is how we apply the blood of Christ to our soul and so find the power of cleansing and forgiveness through the blood of the Lamb.