1 John 4:20

If any one says, I love God, and hates his brother, he is a liar; for he that loves not his brother whom he has seen, how can he love God whom he has not seen?

1 John 2:4

He that says, I have known him, and keeps not his commandments, is a liar, and the truth is not in him;

1 John 2:9

He that says he is in the light, and hates his brother, is in darkness till now.

1 John 3:17

And whoever has the goods of the world and sees his brother have need, and withholds his compassions from him, how continues the love of God in him?

1 John 4:12

No one has ever seen God. If we love one another, God continues in us and his love is perfected in us.

1 John 2:11

but he that hates his brother is in darkness, and walks in darkness, and knows not where he goes, because the darkness has blinded his eyes.

1 Peter 1:8

whom not having seen you love, in whom believing though now you see him not you rejoice with joy unspeakable and glorious,

1 John 1:6

If we say that we have fellowship with him, and walk in darkness, we lie and observe 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 that says, I have known him, and keeps not his commandments, is a liar, and the truth is not in him;
1 John 3:17
And whoever has the goods of the world and sees his brother have need, and withholds his compassions from him, how continues the love of God in him?

Not

1 John 4:12
No one has ever seen God. If we love one another, God continues in us and his love is perfected in us.

General references

Matthew 22:40
On these two commandments hang all the law and the prophets.
Matthew 25:42
For I was hungry and you gave me no food; I was thirsty and you gave me no drink;
John 13:35
By this shall all know that you are my disciples, if you have love one for another.
John 14:15
If you love me, keep my commandments;
Hebrews 13:1
Let brotherly love continue.