1 John 4:20

If anyone says, "I love God," and hates his brother, he is a liar; for he who does not love his brother whom he has seen, cannot love God whom he has not seen.

1 John 2:4

He who says, "I know him," but does not keep his commandments, is a liar, and the truth is not in him.

1 John 2:9

He who says he is in the light and hates his brother is in the darkness still.

1 John 3:17

But if anyone has the world's goods and sees his brother in need, yet closes his heart against him, how does the love of God abide in him?

1 John 4:12

No one has ever seen God; but if we love one another, God abides in us and his love is perfected in us.

1 John 2:11

But he who hates his brother is in the darkness and walks in the darkness, and does not know where he is going, because the darkness has blinded his eyes.

1 Peter 1:8

Though you have not seen him, you love him; and even though you do not see him now, you believe in him and rejoice with an inexpressible and glorious joy,

1 John 1:6

If we say we have fellowship with him, and walk in darkness, we lie and do not live according to 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 who says, "I know him," but does not keep his commandments, is a liar, and the truth is not in him.
1 John 3:17
But if anyone has the world's goods and sees his brother in need, yet closes his heart against him, how does the love of God abide in him?

Not

1 John 4:12
No one has ever seen God; but if we love one another, God abides 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 all men will know that you are my disciples, if you have love for one another."
John 14:15
"If you love me, you will keep my commandments.
Hebrews 13:1
Let brotherly love continue.