Jesus said, "It is the thought-life that defiles you. For from within, out of a person's heart, come evil thoughts..."
When you read all the words in Mark 7:20-23, you get an idea of just how ugly and sinful people can become. And you will find that there are several places in the New Testament where there are other lists of the bad things that people did in those far off times and people do the same things today. The words Jesus uses in the verses above are similar to those the apostle Paul uses and that the apostle Peter uses: they are words of bad company - "vile things ... and make you unacceptable to God" (verse 23).
When we harbour any of these thoughts in our hearts we have to repent of them and ask God for his cleansing and grace in forgiveness. Remember that such thoughts are bad company and make us unacceptable to God. Surely we don't want to live like that ?
But how do we deal with someone who does live like that — a person who loves the ways of the bad company Jesus was speaking about. First of all we must pray for them. They need God's help as only he can give them a sense of shame and a longing to leave the bad company they keep and desire to live a clean life. We must love someone like that and show them our love — a caring love that will want God's best for them. It may be that such a person needs more help than we can give them, but we can help them find such help and by God's grace they may come to find in Jesus the cleansing forgiving Saviour they need.