1 John 1:6

If we say we have fellowship with him, and walk in darkness, we lie and do not the truth.

1 John 4:20

If a man say, I love God, and hateth his brother, he is a liar; for he that loveth not his brother whom he hath seen, how can he love God, whom he hath not seen?

1 John 1:10

If we say, we have not sinned, we make him a liar, and his word is not in us.

John 3:19-21

And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil.

John 12:35

Who is this Son of man? Then Jesus said to them, Yet a little while is the light with you. Walk while ye have the light, lest darkness overtake you, for he that walketh in darkness, knoweth not whither he goeth.

1 John 2:4

He that faith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.

Revelation 3:17-18

Because thou sayst, I am rich, and have inriched myself, and have need of nothing, and knowest not, that thou art wretched, and miserable, and poor, and blind, and naked.

Matthew 7:22

Many will say to me in that day, Lord, Lord, have we not prophesied in thy name, and in thy name have cast out devils, and in thy name have done many wonderful works?

John 8:12

Then spake Jesus again to them, saying, I am the light of the world; he that followeth me, shall not walk in darkness, but shall have the light of life.

John 8:44-45

Ye are of your father the devil, and your will is, to do the desires of your father. He was a murderer from the beginning, and abode not in the truth; for there is no truth in him. When he speaketh a lie, he speaketh of his own; for he is a liar, and the father of it.

John 11:10

But if any man walk in the night, he stumbleth, because the light is not in him.

John 12:46

I am come a light into the world, that whosoever believeth on me, may not continue in darkness.

2 Corinthians 6:14-16

Be not unequally yoked with unbelievers; for what fellowship hath righteousness with unrighteousness? or what communion hath light with darkness?

1 Timothy 4:2

By the hypocrisy of them that speak lies, having their own consciences seared as with an hot iron:

James 2:14

What doth it profit, my brethren, tho' a man say he hath faith, and have not works?

James 2:16

and want daily food, And one of you say to them, Depart in peace; be ye warmed and filled, but give them not the things needful for the body, what doth it profit?

James 2:18

But one will say, Thou hast faith, and I have works. Shew me thy faith without thy works, and I will shew thee my faith by my works.

1 John 1:3

That which we have seen and heard declare we to you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son, Jesus Christ:

1 John 1:8

If we say, we have no sin, we deceive ourselves, and the truth is not in us.

1 John 2:9-11

He that saith, he is in the light, and hateth his brother, is in darkness until now.

Treasury of Scripture Knowledge

Summary

If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:

Do not

Bible References

If

1 John 1:8
If we say, we have no sin, we deceive ourselves, and the truth is not in us.
1 John 2:4
He that faith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.
1 John 4:20
If a man say, I love God, and hateth his brother, he is a liar; for he that loveth not his brother whom he hath seen, how can he love God, whom he hath not seen?
Matthew 7:22
Many will say to me in that day, Lord, Lord, have we not prophesied in thy name, and in thy name have cast out devils, and in thy name have done many wonderful works?
James 2:14
What doth it profit, my brethren, tho' a man say he hath faith, and have not works?
Revelation 3:17
Because thou sayst, I am rich, and have inriched myself, and have need of nothing, and knowest not, that thou art wretched, and miserable, and poor, and blind, and naked.

Fellowship

1 John 1:3
That which we have seen and heard declare we to you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son, Jesus Christ:
2 Corinthians 6:14
Be not unequally yoked with unbelievers; for what fellowship hath righteousness with unrighteousness? or what communion hath light with darkness?

We lie

1 John 1:10
If we say, we have not sinned, we make him a liar, and his word is not in us.
1 John 4:20
If a man say, I love God, and hateth his brother, he is a liar; for he that loveth not his brother whom he hath seen, how can he love God, whom he hath not seen?
John 8:44
Ye are of your father the devil, and your will is, to do the desires of your father. He was a murderer from the beginning, and abode not in the truth; for there is no truth in him. When he speaketh a lie, he speaketh of his own; for he is a liar, and the father of it.
1 Timothy 4:2
By the hypocrisy of them that speak lies, having their own consciences seared as with an hot iron:

Do not

John 3:21
But he that practiseth the truth, cometh to the light, that his deeds may be made manifest that they are wrought in God.