The one absolutely unselfish friend that man can have in this selfish world is his dog

From Ann Althouse, "George Graham Vest served in the United States Senate for twenty-four years, from 1879 to 1903, but the act for which he is best remembered....

From the Senate's site:

The lawsuit that brought him immortality concerned the shooting of "Old Drum," the best hunting dog of a local farmer. A neighbor who suspected that Old Drum was moonlighting by killing his sheep gave orders to shoot the dog if it appeared on the property again. When Old Drum was found dead near the neighbor's house, the farmer filed suit, seeking damages of fifty dollars. After a jury awarded twenty-five dollars, the neighbor successfully appealed the ruling. The dog's owner, however, succeeded in his motion for a new trial and hired two skilled lawyers, one of them George G. Vest.

Vest's speech, Eulogy of the Dog, September 23, 1870, Warrensburg, Missouri.

Gentlemen of the Jury: The best friend a man has in the world may turn against him and become his enemy. His son or daughter that he has reared with loving care may prove ungrateful. Those who are nearest and dearest to us, those whom we trust with our happiness and our good name may become traitors to their faith. The money that a man has, he may lose. It flies away from him, perhaps when he needs it most. A man's reputation may be sacrificed in a moment of ill-considered action. The people who are prone to fall on their knees to do us honor when success is with us, may be the first to throw the stone of malice when failure settles its cloud upon our heads.

The one absolutely unselfish friend that man can have in this selfish world, the one that never deserts him, the one that never proves ungrateful or treacherous is his dog. A man's dog stands by him in prosperity and in poverty, in health and in sickness. He will sleep on the cold ground, where the wintry winds blow and the snow drives fiercely, if only he may be near his master's side. He will kiss the hand that has no food to offer. He will lick the wounds and sores that come in encounters with the roughness of the world. He guards the sleep of his pauper master as if he were a prince. When all other friends desert, he remains. When riches take wings, and reputation falls to pieces, he is as constant in his love as the sun in its journey through the heavens.

If fortune drives the master forth, an outcast in the world, friendless and homeless, the faithful dog asks no higher privilege than that of accompanying him, to guard him against danger, to fight against his enemies. And when the last scene of all comes, and death takes his master in its embrace and his body is laid away in the cold ground, no matter if all other friends pursue their way, there by the graveside will the noble dog be found, his head between his paws, his eyes sad, but open in alert watchfulness, faithful and true even in death.