15 There is nothing outside a person that by going into him can defile him, but the things that come out of a person are what defile him."[1] 17 And when he had entered the house and left the people, his disciples asked him about the parable. 18 And he said to them, "Then are you also without understanding? Do you not see that whatever goes into a person from outside cannot defile him, 19 since it enters not his heart but his stomach, and is expelled?"[2] ( Thus he declared all foods clean.)
Matthew Henry's Commentary on Mark 7:15-19
Commentary on Mark 7:14-23
(Read Mark 7:14-23)
Our wicked thoughts and affections, words and actions, defile us, and these only. As a corrupt fountain sends forth corrupt streams, so does a corrupt heart send forth corrupt reasonings, corrupt appetites and passions, and all the wicked words and actions that come from them. A spiritual understanding of the law of God, and a sense of the evil of sin, will cause a man to seek for the grace of the Holy Spirit, to keep down the evil thoughts and affections that work within.