Titus 1:15

To the pure, everything is pure, but to those who are defiled and unbelieving nothing is pure; in fact, both their mind and conscience are defiled.

Romans 14:20

Do not tear down God’s work because of food. Everything is clean, but it is wrong for a man to cause stumbling by what he eats.

Romans 14:23

But whoever doubts stands condemned if he eats, because his eating is not from a conviction, and everything that is not from a conviction is sin.

Romans 14:14

(I know and am persuaded by the Lord Jesus that nothing is unclean in itself. Still, to someone who considers a thing to be unclean, to that one it is unclean.)

Matthew 15:18

But what comes out of the mouth comes from the heart, and this defiles a man.

Acts 10:15

Again, a second time, a voice said to him, “What God has made clean, you must not call common.”

Proverbs 21:4

The lamp that guides the wicked—
haughty eyes and an arrogant heart—is sin.

Haggai 2:13

Then Haggai asked, “If someone defiled by contact with a corpse touches any of these, does it become defiled?”

The priests answered, “It becomes defiled.”

Zechariah 7:5-6

“Ask all the people of the land and the priests: When you fasted and lamented in the fifth and in the seventh months for these 70 years, did you really fast for Me?

Luke 11:39-41

But the Lord said to him: “Now you Pharisees clean the outside of the cup and dish, but inside you are full of greed and evil.

1 Corinthians 6:12-13

“Everything is permissible for me,” but not everything is helpful. “Everything is permissible for me,” but I will not be brought under the control of anything.

1 Corinthians 8:7

However, not everyone has this knowledge. In fact, some have been so used to idolatry up until now that when they eat food offered to an idol, their conscience, being weak, is defiled.

1 Corinthians 10:23

“Everything is permissible,” but not everything is helpful. “Everything is permissible,” but not everything builds up.

1 Corinthians 10:25

Eat everything that is sold in the meat market, asking no questions for conscience’ sake,

1 Corinthians 10:31

Therefore, whether you eat or drink, or whatever you do, do everything for God’s glory.

1 Corinthians 11:27-29

Therefore, whoever eats the bread or drinks the cup of the Lord in an unworthy way will be guilty of sin against the body and blood of the Lord.

1 Timothy 4:3-4

They forbid marriage and demand abstinence from foods that God created to be received with gratitude by those who believe and know the truth.

1 Timothy 6:5

and constant disagreement among people whose minds are depraved and deprived of the truth, who imagine that godliness is a way to material gain.

Hebrews 9:14

how much more will the blood of the Messiah, who through the eternal Spirit offered Himself without blemish to God, cleanse our consciences from dead works to serve the living God?

Hebrews 10:22

let us draw near with a true heart in full assurance of faith, our hearts sprinkled clean from an evil conscience and our bodies washed in pure water.

Treasury of Scripture Knowledge

Summary

Unto the pure all things are pure: but unto them that are defiled and unbelieving is nothing pure; but even their mind and conscience is defiled.

Bible References

The pure

Luke 11:39
But the Lord said to him: “Now you Pharisees clean the outside of the cup and dish, but inside you are full of greed and evil.
Acts 10:15
Again, a second time, a voice said to him, “What God has made clean, you must not call common.”
Romans 14:14
(I know and am persuaded by the Lord Jesus that nothing is unclean in itself. Still, to someone who considers a thing to be unclean, to that one it is unclean.)
1 Corinthians 6:12
“Everything is permissible for me,” but not everything is helpful. “Everything is permissible for me,” but I will not be brought under the control of anything.
1 Corinthians 10:23
“Everything is permissible,” but not everything is helpful. “Everything is permissible,” but not everything builds up.
1 Timothy 4:3
They forbid marriage and demand abstinence from foods that God created to be received with gratitude by those who believe and know the truth.

Their

1 Corinthians 8:7
However, not everyone has this knowledge. In fact, some have been so used to idolatry up until now that when they eat food offered to an idol, their conscience, being weak, is defiled.
Hebrews 9:14
how much more will the blood of the Messiah, who through the eternal Spirit offered Himself without blemish to God, cleanse our consciences from dead works to serve the living God?
Hebrews 10:22
let us draw near with a true heart in full assurance of faith, our hearts sprinkled clean from an evil conscience and our bodies washed in pure water.

General references

Leviticus 7:19
“Meat that touches anything unclean must not be eaten; it is to be burned up. Everyone who is clean may eat any other meat.
Leviticus 10:10
You must distinguish between the holy and the common, and the clean and the unclean,
Leviticus 11:34
Any edible food coming into contact with that unclean water will become unclean, and any drinkable liquid in any container will become unclean.
Deuteronomy 14:3
“You must not eat any detestable thing.
Acts 24:16
I always do my best to have a clear conscience toward God and men.

Holman Christian Standard Bible®, Copyright © 1999, 2000, 2002, 2003, 2009 by Holman Bible Publishers.