vs 3 says
You are already clean because of the word which I have given you [the teachings which I have discussed with you].
I can summarize it by saying
The farther you are from the Word of God, the filthier your life becomes.
My point can be buttressed with Psalm. 119:11 which says
Your word I have hidden in my heart, That I might not sin against You.
So if you stay away from God's word, you will find it very difficult to live a righteous life.