I have a house with a pool down in Florida, and when I bought the house, I could not see the bottom of the pool.  It was filled with scum, dirt and algae.  Things were growing in the pool and not in a good way.  It had a shallow end and a deep end.  I had a pool company come out and inspect the pool.  The service representative said He would not service it because he was concerned there might be a gator inside. 

A pool is like our body.   Outside of Christ, we are dirty and need to be cleaned up.    God says we are like filthy rags. We have a lot on the inside that is not of God… unforgiveness, bitterness, greed, pride, selfishness, etc.   And until we accept Jesus as our Savour, we really don’t know how filthy we are or what sins need to be repented of.

Jesus said, we are to “First clean the inside of the cup and dish, and then the outside also will be clean.”  Mathew 23:26