1 John 1:6

If we claim to share a relationship with God and yet live in darkness [i.e., in a sinful way], we are lying and are not living a truthful life.

1 John 4:20

If a person says, "I love God," yet [in reality] hates his brother, he is a liar. For the person who does not love his brother, whom he has seen, cannot [possibly] love God, whom he has never seen.

1 John 1:10

If we claim that we have not committed sins, we are [in effect] calling God a liar [i.e., because He says we have] and His word [i.e., the real truth about the matter] is not in our hearts.

John 3:19-21

Now this is [how God's] judgment [works]: The Light [See 1:5-9] has come into the world, but people loved darkness [i.e., sin] rather than the Light, because their deeds were evil.

John 12:35

So, Jesus said to them, "The Light will be among you for only a little while [longer]. Walk around while you [still] have the Light [with you], before darkness surrounds you. For the person who walks around in darkness does not know where he is going.

1 John 2:4

The person who says, "I have come to know Him," but does not obey what He commands, is lying [by such a profession], and the truth [about the matter] is not in his heart.

Revelation 3:17-18

For you are saying, 'I am wealthy; I have made plenty of money and do not need anything.' But you do not know that you are [spiritually] wretched and miserable and poor and blind and naked.

Matthew 7:22

Many persons will say to me on the [judgment] day, 'Lord, Lord, did we not prophesy by [the authority of] your name, and drive out evil spirits and perform many powerful [supernatural] deeds by your name?'

John 8:12

So, Jesus spoke to them again [i.e., to the Jewish authorities. See 7:45], saying, "I am the light of the world. The person who becomes my follower will never live in [spiritual] darkness, but have the light of [i.e., for his] life [i.e., followers of Jesus will not live in error and sin but in truth and righteousness]."

John 8:44-45

You belong to your father the devil, and you are [always] wanting to do what your father desires. He was a murderer from the [very] beginning [Note: This is probably a reference to Satan's influence on Adam, Eve and Cain in the Garden of Eden] and does not stand for the truth, because there is no truth in him. When he lies, he only speaks what is part of his nature, because he is a liar and the father of [all] liars.

John 11:10

But if he walks at night he [might] stumble, because there is no light [to see by]. [Note: These words have a figurative meaning as Jesus is speaking about His mission in life].

John 12:46

I have come into the world to be a light [to it], so that whoever believes in me would not have to remain in [spiritual] darkness.

2 Corinthians 6:14-16

Do not team up with unbelievers [i.e., in close relationships, such as marriage, etc.]. For what do righteousness and wickedness have in common? Or, what fellowship can light have with darkness?

1 Timothy 4:2

[Such teaching will be spread] by hypocritical liars, whose consciences have been seared over as with a hot iron [i.e., making them insensitive to their guilt].

James 2:14

What good is it, my brothers [and sisters], if a person says he has faith but does not have [good] deeds? Can such faith save him?

James 2:16

and one of you says to him, "Go [and be] at peace; keep warm and eat well," and yet you do not give him anything for his physical needs, what good is that?

James 2:18

But someone may say, "You have faith and I have [good] deeds." [I reply], show me your faith without your [good] deeds, and I will show you my faith by my [good] deeds.

1 John 1:3

We declare to you what we have seen and heard [concerning Christ], so that you also may share a relationship with us. And indeed, our fellowship is with the Father and with His Son Jesus Christ.

1 John 1:8

If we claim to have no sinful practices [in our lives], we are self-deceived and are not being truthful about the matter.

1 John 2:9-11

The person who claims to be living in [harmony with] the light [i.e., by obeying God's truth], and [yet] hates his brother is still [living] in the darkness [of sin].

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 claim to have no sinful practices [in our lives], we are self-deceived and are not being truthful about the matter.
1 John 2:4
The person who says, "I have come to know Him," but does not obey what He commands, is lying [by such a profession], and the truth [about the matter] is not in his heart.
1 John 4:20
If a person says, "I love God," yet [in reality] hates his brother, he is a liar. For the person who does not love his brother, whom he has seen, cannot [possibly] love God, whom he has never seen.
Matthew 7:22
Many persons will say to me on the [judgment] day, 'Lord, Lord, did we not prophesy by [the authority of] your name, and drive out evil spirits and perform many powerful [supernatural] deeds by your name?'
James 2:14
What good is it, my brothers [and sisters], if a person says he has faith but does not have [good] deeds? Can such faith save him?
Revelation 3:17
For you are saying, 'I am wealthy; I have made plenty of money and do not need anything.' But you do not know that you are [spiritually] wretched and miserable and poor and blind and naked.

Fellowship

1 John 1:3
We declare to you what we have seen and heard [concerning Christ], so that you also may share a relationship with us. And indeed, our fellowship is with the Father and with His Son Jesus Christ.
2 Corinthians 6:14
Do not team up with unbelievers [i.e., in close relationships, such as marriage, etc.]. For what do righteousness and wickedness have in common? Or, what fellowship can light have with darkness?

We lie

1 John 1:10
If we claim that we have not committed sins, we are [in effect] calling God a liar [i.e., because He says we have] and His word [i.e., the real truth about the matter] is not in our hearts.
1 John 4:20
If a person says, "I love God," yet [in reality] hates his brother, he is a liar. For the person who does not love his brother, whom he has seen, cannot [possibly] love God, whom he has never seen.
John 8:44
You belong to your father the devil, and you are [always] wanting to do what your father desires. He was a murderer from the [very] beginning [Note: This is probably a reference to Satan's influence on Adam, Eve and Cain in the Garden of Eden] and does not stand for the truth, because there is no truth in him. When he lies, he only speaks what is part of his nature, because he is a liar and the father of [all] liars.
1 Timothy 4:2
[Such teaching will be spread] by hypocritical liars, whose consciences have been seared over as with a hot iron [i.e., making them insensitive to their guilt].

Do not

John 3:21
But the person who does what is [according to the] truth [i.e., good things] comes to the light so that his deeds may be shown to have been produced by God.