The Jews of Jesus’ day were very concerned about ritual rules, such as not eating specific foods and not eating without first ceremonially washing their hands. But Jesus showed that it is not what we take in (eat) that defiles us but what comes out of our hearts, such as (see verses 21 and 22) evil thoughts, sexual sin, murder, theft, envy of others’ possessions, blasphemy, and the like.
And we pray:
Lord Jesus, you taught us truly that true religion is of the heart and that defilment comes from within. Out of the heart are the issues of life. (Proverbs 4:23) Search me, O God, and know my heart today, see if there be some wicked way in me, cleanse me from every sin and set me free. Amen.