Chapter 7:17 When he had left the crowd and entered the house, His disciples questioned Him about the parable.
Chapter 7:18 And He said to them, “Are you so lacking in understanding also? Do you not understand that whatever goes into a man from outside cannot defile him,
What Jesus is saying to the disciples is that sin comes from the heart. So for the Jew who ate “unclean” food this was not caused by the food itself but by the heart that acted in disobedience to God. When we truly understand this, we begin to understand sin, its progression and its effects on our lives. Understand the progression of sin (James 1:15) The progression of sin is frightening and certain: lust, sin, and death.