John 6:22-71 (NIV)
22 The next day the crowd that had stayed on the opposite shore of the lake realized that only one boat had been there, and that Jesus had not entered it with his disciples, but that they had gone away alone. 23 Then some boats from Tiberias landed near the place where the people had eaten the bread after the Lord had given thanks. 24 Once the crowd realized that neither Jesus nor his disciples were there, they got into the boats and went to Capernaum in search of Jesus.
Jesus the Bread of Life
25 When they found him on the other side of the lake, they asked him, “Rabbi, when did you get here?”
26 Jesus answered, “Very truly I tell you, you are looking for me, not because you saw the signs I performed but because you ate the loaves and had your fill. 27 Do not work for food that spoils, but for food that endures to eternal life, which the Son of Man will give you. For on him God the Father has placed his seal of approval.”
28 Then they asked him, “What must we do to do the works God requires?”
29 Jesus answered, “The work of God is this: to believe in the one he has sent.”
30 So they asked him, “What sign then will you give that we may see it and believe you? What will you do? 31 Our ancestors ate the manna in the wilderness; as it is written: ‘He gave them bread from heaven to eat.’”
32 Jesus said to them, “Very truly I tell you, it is not Moses who has given you the bread from heaven, but it is my Father who gives you the true bread from heaven. 33 For the bread of God is the bread that comes down from heaven and gives life to the world.”
34 “Sir,” they said, “always give us this bread.”
35 Then Jesus declared, “I am the bread of life. Whoever comes to me will never go hungry, and whoever believes in me will never be thirsty. 36 But as I told you, you have seen me and still you do not believe. 37 All those the Father gives me will come to me, and whoever comes to me I will never drive away. 38 For I have come down from heaven not to do my will but to do the will of him who sent me. 39 And this is the will of him who sent me, that I shall lose none of all those he has given me, but raise them up at the last day. 40 For my Father’s will is that everyone who looks to the Son and believes in him shall have eternal life, and I will raise them up at the last day.”
41 At this the Jews there began to grumble about him because he said, “I am the bread that came down from heaven.” 42 They said, “Is this not Jesus, the son of Joseph, whose father and mother we know? How can he now say, ‘I came down from heaven’?”
43 “Stop grumbling among yourselves,” Jesus answered. 44 “No one can come to me unless the Father who sent me draws them, and I will raise them up at the last day. 45 It is written in the Prophets: ‘They will all be taught by God.’ Everyone who has heard the Father and learned from him comes to me. 46 No one has seen the Father except the one who is from God; only he has seen the Father. 47 Very truly I tell you, the one who believes has eternal life.48 I am the bread of life. 49 Your ancestors ate the manna in the wilderness, yet they died.50 But here is the bread that comes down from heaven, which anyone may eat and not die.51 I am the living bread that came down from heaven. Whoever eats this bread will live forever. This bread is my flesh, which I will give for the life of the world.”
52 Then the Jews began to argue sharply among themselves, “How can this man give us his flesh to eat?”
53 Jesus said to them, “Very truly I tell you, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you. 54 Whoever eats my flesh and drinks my blood has eternal life, and I will raise them up at the last day. 55 For my flesh is real food and my blood is real drink. 56 Whoever eats my flesh and drinks my blood remains in me, and I in them. 57 Just as the living Father sent me and I live because of the Father, so the one who feeds on me will live because of me. 58 This is the bread that came down from heaven. Your ancestors ate manna and died, but whoever feeds on this bread will live forever.” 59 He said this while teaching in the synagogue in Capernaum.
Many Disciples Desert Jesus
60 On hearing it, many of his disciples said, “This is a hard teaching. Who can accept it?”
61 Aware that his disciples were grumbling about this, Jesus said to them, “Does this offend you? 62 Then what if you see the Son of Man ascend to where he was before! 63 The Spirit gives life; the flesh counts for nothing. The words I have spoken to you—they are full of the Spirit and life. 64 Yet there are some of you who do not believe.” For Jesus had known from the beginning which of them did not believe and who would betray him. 65 He went on to say, “This is why I told you that no one can come to me unless the Father has enabled them.”
66 From this time many of his disciples turned back and no longer followed him.
67 “You do not want to leave too, do you?” Jesus asked the Twelve.
68 Simon Peter answered him, “Lord, to whom shall we go? You have the words of eternal life. 69 We have come to believe and to know that you are the Holy One of God.”
70 Then Jesus replied, “Have I not chosen you, the Twelve? Yet one of you is a devil!” 71 (He meant Judas, the son of Simon Iscariot, who, though one of the Twelve, was later to betray him.)
Mark 7:1-23 (NIV)
That Which Defiles
7 The Pharisees and some of the teachers of the law who had come from Jerusalem gathered around Jesus 2 and saw some of his disciples eating food with hands that were defiled, that is, unwashed. 3 (The Pharisees and all the Jews do not eat unless they give their hands a ceremonial washing, holding to the tradition of the elders. 4 When they come from the marketplace they do not eat unless they wash. And they observe many other traditions, such as the washing of cups, pitchers and kettles.)
5 So the Pharisees and teachers of the law asked Jesus, “Why don’t your disciples live according to the tradition of the elders instead of eating their food with defiled hands?”
6 He replied, “Isaiah was right when he prophesied about you hypocrites; as it is written:
“‘These people honor me with their lips,
but their hearts are far from me.
7 They worship me in vain;
their teachings are merely human rules.’
8 You have let go of the commands of God and are holding on to human traditions.”
9 And he continued, “You have a fine way of setting aside the commands of God in order to observe your own traditions! 10 For Moses said, ‘Honor your father and mother,’ and, ‘Anyone who curses their father or mother is to be put to death.’ 11 But you say that if anyone declares that what might have been used to help their father or mother is Corban (that is, devoted to God)— 12 then you no longer let them do anything for their father or mother. 13 Thus you nullify the word of God by your tradition that you have handed down. And you do many things like that.”
14 Again Jesus called the crowd to him and said, “Listen to me, everyone, and understand this. 15 Nothing outside a person can defile them by going into them. Rather, it is what comes out of a person that defiles them.” 
17 After he had left the crowd and entered the house, his disciples asked him about this parable. 18 “Are you so dull?” he asked. “Don’t you see that nothing that enters a person from the outside can defile them? 19 For it doesn’t go into their heart but into their stomach, and then out of the body.” (In saying this, Jesus declared all foods clean.)
20 He went on: “What comes out of a person is what defiles them. 21 For it is from within, out of a person’s heart, that evil thoughts come—sexual immorality, theft, murder, 22 adultery, greed, malice, deceit, lewdness, envy, slander, arrogance and folly. 23 All these evils come from inside and defile a person.”
Matthew 15:1-20 (NIV)
That Which Defiles
15 Then some Pharisees and teachers of the law came to Jesus from Jerusalem and asked,2 “Why do your disciples break the tradition of the elders? They don’t wash their hands before they eat!”
3 Jesus replied, “And why do you break the command of God for the sake of your tradition?4 For God said, ‘Honor your father and mother’ and ‘Anyone who curses their father or mother is to be put to death.’ 5 But you say that if anyone declares that what might have been used to help their father or mother is ‘devoted to God,’ 6 they are not to ‘honor their father or mother’ with it. Thus you nullify the word of God for the sake of your tradition. 7 You hypocrites! Isaiah was right when he prophesied about you:
8 “‘These people honor me with their lips,
but their hearts are far from me.
9 They worship me in vain;
their teachings are merely human rules.’”
10 Jesus called the crowd to him and said, “Listen and understand. 11 What goes into someone’s mouth does not defile them, but what comes out of their mouth, that is what defiles them.”
12 Then the disciples came to him and asked, “Do you know that the Pharisees were offended when they heard this?”
13 He replied, “Every plant that my heavenly Father has not planted will be pulled up by the roots. 14 Leave them; they are blind guides. If the blind lead the blind, both will fall into a pit.”
15 Peter said, “Explain the parable to us.”
16 “Are you still so dull?” Jesus asked them. 17 “Don’t you see that whatever enters the mouth goes into the stomach and then out of the body? 18 But the things that come out of a person’s mouth come from the heart, and these defile them. 19 For out of the heart come evil thoughts—murder, adultery, sexual immorality, theft, false testimony, slander. 20 These are what defile a person; but eating with unwashed hands does not defile them.”