John 6:43-51, 60, 66; Mark 7:5-8,14-23

"Stop grumbling among yourselves," Jesus answered.
"No one can come to Me
unless the Father who sent Me draws him,
and I will raise him up at the last day.
It is written in the Prophets:
'They will all be taught by God.' (Isa. 54:13)
Everyone who listens to the Father
and learns from Him comes to me.
No one has seen the Father except the one who is from God;
only He has seen the Father.
I tell you the truth,
He who believes has everlasting life.
I am the bread of life.
Your forefathers ate the manna in the desert,
yet they died.
But here is the bread that comes down from heaven,
which a man may eat and not die.
I am the living bread that came down from heaven.
If anyone eats of this bread,
he will live forever.
This bread is My flesh,
which I will give for the life of the world."
On hearing it, many of His disciples said,
"This is a hard teaching.  Who can accept it?"
From this time many of His disciples turned back
and no longer followed Him.
(John 6:43-51, 60, 66) NIV

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 wit 'unclean' hands?"
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.
They worship me in vain;
their teachings are but rules taught by men.'  (Isa. 29:13)
You have let go of the commands of God
and are holding on to the traditions of men."
Again Jesus called the crowd to Him and said,
"Listen to me, everyone, and understand this.
Nothing  outside a man can make him 'unclean'
by going into him.
Rather, it is what comes of of a man
that makes him unclean."
After He had left the crowd and entered the house,
His disciples asked Him about this parable.
"Are you so dull?" He asked.
"Don't you see
that nothing that enters a man from the outside
can make him 'unclean'?
For it doesn't go into his heart
but into his stomach,
and then out of his body."
(In saying this,
Jesus declared all food "clean.")
He went on:
"What comes out of a man is what makes him 'unclean.'
For from within, out of men's hearts,
come all evil thoughts, sexual immorality,
theft murder, adultery, greed, malice, deceit,
lewdness, envy, slander arrogance and folly.
All these evils come from inside
and make a man 'unclean.'"
(Mark 75-8,14-23) NIV