Matthew 15:11 NIV

1 Timothy 4:4-5 NIV
For everything God created is good, and nothing is to be rejected if it is received with thanksgiving, because it is consecrated by the word of God and prayer.

James 3:5-8 NIV
Likewise, the tongue is a small part of the body, but it makes great boasts. Consider what a great forest is set on fire by a small spark. The tongue also is a fire, a world of evil among the parts of the body. It corrupts the whole body, sets the whole course of one’s life on fire, and is itself set on fire by hell. All kinds of animals, birds, reptiles and sea creatures are being tamed and have been tamed by mankind, but no human being can tame the tongue. It is a restless evil, full of deadly poison.

Luke 11:38-41 NIV
But the Pharisee was surprised when he noticed that Jesus did not first wash before the meal. Then the Lord said to him, “Now then, you Pharisees clean the outside of the cup and dish, but inside you are full of greed and wickedness. You foolish people! Did not the one who made the outside make the inside also? But now as for what is inside you—be generous to the poor, and everything will be clean for you.

Mark 7:15 NIV
Nothing outside a person can defile them by going into them. Rather, it is what comes out of a person that defiles them.”

Matthew 12:34-37 NIV
You brood of vipers, how can you who are evil say anything good? For the mouth speaks what the heart is full of. A good man brings good things out of the good stored up in him, and an evil man brings evil things out of the evil stored up in him. But I tell you that everyone will have to give account on the day of judgment for every empty word they have spoken. For by your words you will be acquitted, and by your words you will be condemned.”

Matthew 15:18-20 NIV
But the things that come out of a person’s mouth come from the heart, and these defile them. For out of the heart come evil thoughts—murder, adultery, sexual immorality, theft, false testimony, slander. These are what defile a person; but eating with unwashed hands does not defile them.”