The Bible always tells us to live a life in holiness before the Lord, and is that we can not pretend to be followers of Christ if we live a life under sin, if we are really Christians we have to live as such, as the Scriptures teach us, our whole Christian life is based on living for the Lord and living in the Lord.
The apostle Peter wrote:
8 For if you possess these qualities in increasing measure, they will keep you from being ineffective and unproductive in your knowledge of our Lord Jesus Christ.
9 But whoever does not have them is nearsighted and blind, forgetting that they have been cleansed from their past sins.
10 Therefore, my brothers and sisters, make every effort to confirm your calling and election. For if you do these things, you will never stumble,
2 Peter 1:8-10