The Pharisees were upset because the disciples ignored the tradition of ceremonial washing before eating. Jesus told them you are not defiled by what goes in your mouth but by the words that come out.
1 Then Pharisees and scribes came to Jesus from Jerusalem and said,2 “Why do your disciples break the tradition of the elders? For they do not wash their hands when they eat.”3 He answered them, “And why do you break the commandment of God for the sake of your tradition?4 For God commanded, ‘Honor your father and your mother,’ and, ‘Whoever reviles father or mother must surely die.’5 But you say, ‘If anyone tells his father or his mother, “What you would have gained from me is given to God,”6 he need not honor his father.’ So for the sake of your tradition you have made void the word of God.7 You hypocrites! Well did Isaiah prophesy of you, when he said:8 “‘This people honors me with their lips, but their heart is far from me;9 in vain do they worship me, teaching as doctrines the commandments of men.’”10 And he called the people to him and said to them, “Hear and understand:11 it is not what goes into the mouth that defiles a person, but what comes out of the mouth; this defiles a person.”12 Then the disciples came and said to him, “Do you know that the Pharisees were offended when they heard this saying?”13 He answered, “Every plant that my heavenly Father has not planted will be rooted up.14 Let them alone; they are blind guides. And if the blind lead the blind, both will fall into a pit.”15 But Peter said to him, “Explain the parable to us.”16 And he said, “Are you also still without understanding?17 Do you not see that whatever goes into the mouth passes into the stomach and is expelled?18 But what comes out of the mouth proceeds from the heart, and this defiles a person.19 For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false witness, slander.20 These are what defile a person. But to eat with unwashed hands does not defile anyone.”
