1 John 4:20

If any say, I love God, and hate his brother, he is a liar: for he not loving his brother whom he has seen, God whom he has not seen, how can he love?

1 John 2:4

He saying, I have known him, and not keeping his commands, is a liar, and in him is not the truth.

1 John 2:9

He saying he is in the light, and hating his brother, is in the darkness even until now.

1 John 3:17

And whoever has the life of the world, and sees his brother having need, and should shut up his bowels from him, how remains the love of God in him?

1 John 4:12

None has ever seen God. If we love one another, God remains in us, and his love is completed in us.

1 John 2:11

And he hating his brother is in darkness, and walks about in darkness, and knows not where he goes forward, for darkness has blinded his eyes.

1 Peter 1:8

Whom not having seen, ye love; in whom, now not seeing, but believing, ye are transported with joy unalterable, and highly valued:

1 John 1:6

If we say that we have communion with him, and walk in darkness, we are deceived, and do not the truth:

Treasury of Scripture Knowledge

Summary

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?

Bible References

A man

1 John 2:4
He saying, I have known him, and not keeping his commands, is a liar, and in him is not the truth.
1 John 3:17
And whoever has the life of the world, and sees his brother having need, and should shut up his bowels from him, how remains the love of God in him?

Not

1 John 4:12
None has ever seen God. If we love one another, God remains in us, and his love is completed in us.

General references

Matthew 22:40
In these two commands hang the whole law and the prophets.
Matthew 25:42
For I was hungry, and ye gave me not to eat; I was thirsty, and ye gave me no drink;
John 13:35
In this all shall know that ye are disciples to me, if ye have love in one another.
John 14:15
If ye love me, keep my commands.
Hebrews 13:1
Let brotherly love remain.