Our Scripture reading today is 2 Corinthians 7:1, "Having therefore these promises, dearly beloved, let us cleanse ourselves from all filthiness of the flesh and spirit, perfecting holiness in the fear of God."
In order to get the full impact of this verse, we need to look back to the last verse of chapter six.  Here we find the promise from God that He is our Father and we are His child.  The promises of God are a great incentive to us living in holiness and the fear of God.  There is no doubt in my mind that He will always do His part when we are faithful to do ours.  It is very important that we keep ourselves as far away from the world as possible.  As God's children, we need to be separated from the world and unto Jesus Christ.  Both of these can be seen in 2 Corinthians 7:1 - "cleanse ourselves from all filthiness" and "perfecting holiness."  It is not enough to say we are not like the world.  We also need to strive to be more like Christ!    
The cleansing of ourselves is in connection with God cleansing us.  1 John 1:9 tells us that God is faithful to cleanse us from all unrighteousness if we are willing to confess (agree with God) our sin to God.  We initiate the cleansing by recognizing we need it.  “How can those expect God to purify their hearts who are continually indulging their eyesears, and hands in what is forbidden, and in what tends to increase and bring into action all the evil propensities of the soul?” (Clarke)
As we claim His promises, we do so after seeking His cleansing.