1 Corinthians 6

19 Sometimes Christians do sinful things, and it can be a serious problem, but this does not mean they stop being Christians. Some Christians are ignorant of their own sins until they are revealed either by the word of God, or by another Christian (also based on the Scripture, of course). Others give in to their temptations, despite knowing what is right or wrong. The Christian who has erred still has the Holy Spirit living inside him because the Spirit is a permanent gift from God to every believer. This is something that the Corinthians needed to be assured of, and there are many Christians today who also need to understand this.