Romans 14:14

I have known, and am persuaded, in the Lord Jesus, that nothing is unclean of itself, except to him who is reckoning anything to be unclean -- to that one it is unclean;

1 Corinthians 8:7

but not in all men is the knowledge, and certain with conscience of the idol, till now, as a thing sacrificed to an idol do eat it, and their conscience, being weak, is defiled.

Romans 14:2

one doth believe that he may eat all things -- and he who is weak doth eat herbs;

Romans 14:20

for the sake of victuals cast not down the work of God; all things, indeed, are pure, but evil is to the man who is eating through stumbling.

Acts 10:14-15

And Peter said, 'Not so, Lord; because at no time did I eat anything common or unclean;'

Acts 10:28

And he said unto them, 'Ye know how it is unlawful for a man, a Jew, to keep company with, or to come unto, one of another race, but to me God did shew to call no man common or unclean;

1 Corinthians 8:10

for if any one may see thee that hast knowledge in an idol's temple reclining at meat -- shall not his conscience -- he being infirm -- be emboldened to eat the things sacrificed to idols,

Acts 11:8-9

and I said, Not so, Lord; because anything common or unclean hath at no time entered into my mouth;

Romans 14:23

and he who is making a difference, if he may eat, hath been condemned, because it is not of faith; and all that is not of faith is sin.

1 Corinthians 10:25

Whatever in the meat-market is sold eat ye, not inquiring, because of the conscience,

1 Timothy 4:4

because every creature of God is good, and nothing is to be rejected, with thanksgiving being received,

Titus 1:15

all things, indeed, are pure to the pure, and to the defiled and unstedfast is nothing pure, but of them defiled are even the mind and the conscience;

Treasury of Scripture Knowledge

Summary

I know, and am persuaded by the Lord Jesus, that there is nothing unclean of itself: but to him that esteemeth any thing to be unclean, to him it is unclean.

And am

Bible References

And am

Acts 10:28
And he said unto them, 'Ye know how it is unlawful for a man, a Jew, to keep company with, or to come unto, one of another race, but to me God did shew to call no man common or unclean;

That there

Romans 14:2
one doth believe that he may eat all things -- and he who is weak doth eat herbs;
1 Corinthians 10:25
Whatever in the meat-market is sold eat ye, not inquiring, because of the conscience,
1 Timothy 4:4
because every creature of God is good, and nothing is to be rejected, with thanksgiving being received,
Titus 1:15
all things, indeed, are pure to the pure, and to the defiled and unstedfast is nothing pure, but of them defiled are even the mind and the conscience;

Unclean

Acts 10:14
And Peter said, 'Not so, Lord; because at no time did I eat anything common or unclean;'
Acts 11:8
and I said, Not so, Lord; because anything common or unclean hath at no time entered into my mouth;

To him it

Romans 14:23
and he who is making a difference, if he may eat, hath been condemned, because it is not of faith; and all that is not of faith is sin.
1 Corinthians 8:7
but not in all men is the knowledge, and certain with conscience of the idol, till now, as a thing sacrificed to an idol do eat it, and their conscience, being weak, is defiled.

General references

Leviticus 7:19
'And the flesh which cometh against any unclean thing is not eaten; with fire it is burnt; as to the flesh, every clean one doth eat of the flesh;
Leviticus 11:2
Speak unto the sons of Israel, saying, This is the beast which ye do eat out of all the beasts which are on the earth:
Deuteronomy 14:3
'Thou dost not eat any abominable thing;