COMPLETE COLLECTION OF POEMS By Rudyard Kipling

Now this is the Law of the Jungle — as old and as true as the sky;
And the Wolf that shall keep it may prosper, but the Wolf that shall break it must die.
As the creeper that girdles the tree-trunk the Law runneth forward and back —
For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack.

From The Law of the Jungle