This verse speaks to the fact that the Lord Jesus Christ has washed us and made us clean by His shed blood.
We are cleansed by faith in the WordOfTheLord.
The initial, continual and eternal cleansing of all condemnation for sin is by faith. So also is our victory over every attack of the enemy.
Faith in the Word requires us to hear the Word, to understand the Word and to receive the Word so that our minds and hearts are transformed by it.