1 Thessalonians 4:9

"But as touching brotherly love ye need not that I write unto you: for ye yourselves are taught of God to love one another."

Cross References (ranked by relevance)

Romans 12:10 13

Be kindly affectioned one to another with brotherly love; in honour preferring one another;

Hebrews 13:1

Let brotherly love continue.

1 Peter 4:8

And above all things have fervent charity among yourselves: for charity shall cover the multitude of sins.

Acts 4:32

And the multitude of them that believed were of one heart and of one soul: neither said any of them that ought of the things which he possessed was his own; but they had all things common.

1 Thessalonians 5:1

But of the times and the seasons, brethren, ye have no need that I write unto you.

2 Peter 1:7

And to godliness brotherly kindness; and to brotherly kindness charity.

Hebrews 10:16

This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them;

John 14:26

But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.

1 Peter 3:8

Finally, be ye all of one mind, having compassion one of another, love as brethren, be pitiful, be courteous:

Leviticus 19:8

Therefore every one that eateth it shall bear his iniquity, because he hath profaned the hallowed thing of the LORD: and that soul shall be cut off from among his people.

Psalm 133:1

Behold, how good and how pleasant it is for brethren to dwell together in unity!

Matthew 22:39

And the second is like unto it, Thou shalt love thy neighbour as thyself.

Jeremiah 31:34

And they shall teach no more every man his neighbour, and every man his brother, saying, Know the LORD: for they shall all know me, from the least of them unto the greatest of them, saith the LORD: for I will forgive their iniquity, and I will remember their sin no more.

Isaiah 51:13

And forgettest the LORD thy maker, that hath stretched forth the heavens, and laid the foundations of the earth; and hast feared continually every day because of the fury of the oppressor, as if he were ready to destroy? and where is the fury of the oppressor?