18 Jesus said, "Are you being willfully stupid? Don't you see that what you swallow can't contaminate you? 19 It doesn't enter your heart but your stomach, works its way through the intestines, and is finally flushed." (That took care of dietary quibbling; Jesus was saying that all foods are fit to eat.)
Matthew Henry's Commentary on Mark 7:18-19
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.