As we read this passage, look for examples of traditions of the Pharisees. Verse 4 says they observed many other traditions. What is the difference between a good tradition an a bad tradition. Have you found this to be true.
Someone explain the example with the parents.
Thus you nullify the word of God by your tradition that you have handed down. Nothing outside a man can make him 'unclean' by going into him. We read of Pharisees, Sadducees, and Herodians. One man is called a Zealot. From other sources we learn of the Essenes.