‘Brotherhood’ is about the strength within friendship and that it is everlasting.

What is it then, the human heart ?
From which the sweetest blessings flow,
It makes us from the beasts apart,
Our sentiment they do not know.
It spans the seas from shore to shore,
With it the bond of friendship forms,
Conquering that we may deplore,
In grievous strife of mortal storms.
It ruled the world in ages past,
Pestilence and disaster through,
And through all eternity it will last,
There never was a word more true.
Thus the heart, the love, the clan,
The brotherhood of thoughtful man

— John Davison