One of the basic needs of mankind is food which has also become a sign of communion. Hence, there are such things like communion sacrifices or ritual food. Many religions have dietary laws in which some type of food are forbidden and would render a practitioner of a particular religion ritually unclean. This was the context of the discussion about food in Mark 7:14-23.
14 Again Jesus called the crowd to him and said, “Listen to me, everyone, and understand this. 15 Nothing outside a person can defile them by going into them. Rather, it is what comes out of a person that defiles them.” 
17 After he had left the crowd and entered the house, his disciples asked him about this parable. 18 “Are you so dull?” he asked. “Don’t you see that nothing that enters a person from the outside can defile them? 19 For it doesn’t go into their heart but into their stomach, and then out of the body.” (In saying this, Jesus declared all foods clean.)
20 He went on: “What comes out of a person is what defiles them. 21 For it is from within, out of a person’s heart, that evil thoughts come—sexual immorality, theft, murder, 22 adultery, greed, malice, deceit, lewdness, envy, slander, arrogance and folly. 23 All these evils come from inside and defile a person.” Mark 7:14-23 New International Version (NIV)
Jesus made a very radical teaching about food. He pronounced all foods clean and also pointed out that what is really unclean is actually that which comes out from the heart. As Jesus said, it is from within, from men’s hearts, that evil intentions emerge: fornication, theft, murder, adultery, avarice, malice, deceit, indecency, envy, slander, pride, folly. All these evil things come from within and make a man unclean.
The question now is, what is the state of our hearts? If there is sin, have we sought forgiveness and healing from the Lord? Let us remember that God and sin cannot exist together in our hearts. May our hearts be pure so that our lives will be holy.
Peace and Joy
Written by Rev. Fr. Courage Dogbey