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 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 2:9

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

1 John 3:17

But whoso hath this world's good, and seeth his brother have need, and shutteth up his bowels of compassion from him, how dwelleth the love of God in him?

1 John 4:12

No man hath seen God at any time. If we love one another, God abideth in us, and his love is perfected in us.

1 John 2:11

But he that hateth his brother, is in darkness, and walketh in darkness, and knoweth not whither he goeth, because darkness hath blinded his eyes.

1 Peter 1:8

Whom having not seen, ye love: in whom tho' ye see him not, yet believing, ye rejoice with joy unspeakable and full of glory, Receiving the end of your faith, the salvation of your souls.

1 John 1:6

If we say we have fellowship with him, and walk in darkness, we lie 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 that faith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.
1 John 3:17
But whoso hath this world's good, and seeth his brother have need, and shutteth up his bowels of compassion from him, how dwelleth the love of God in him?

Not

1 John 4:12
No man hath seen God at any time. If we love one another, God abideth in us, and his love is perfected in us.

General references

Matthew 22:40
hang all the law and the prophets.
Matthew 25:42
For I was hungry, and ye gave me no meat; I was thirsty, and ye gave me no drink:
John 13:35
By this shall all men know that ye are my disciples, if ye have love one to another.
John 14:15
If ye love me, keep my commandments. And I will ask the Father, and he will give you another Comforter,
Hebrews 13:1
Let brotherly love continue.