The motto of the United States is "e pluribus unum", or "from many, one." Originally, this referred to the one union formed from the many states. It … - Harry V. Jaffa

What exactly did these words, of both the Declaration of Independence and the Gettysburg Address, mean? They meant that there was no difference, between one human being, and another human being, that made one the master and the other the servant. As Jefferson once put it, some men are not born with saddles on their backs, nor are others born booted and spurred to ride them. That a man or woman rides a horse corresponds with the difference in their natures. No injustice is done to the horse! That an ox should pull a plow, while a man walks behind, is according to nature. In these cases, servitude follows from the laws of nature. But these same laws of nature tell us that when a human being is subjected to other human beings as if he were a horse or an ox, the laws of nature are violated. All human beings are accordingly equal in their right not to be enslaved, and in their right to be in secure possession of their lives, liberties, and property. To this end they have a right to be governed only by laws to which they have consented.

[T]he one unforgivable sin, according to dominant Southern public opinion, was moral condemnation of slavery.

Slavery in the British colonies of North America was more than a century-and-a-half old before independence. It was roundly condemned, at one time or another, by nearly all the important political personages of the Revolution. I know of no instance in which any of these personages contradicted the doctrine of the Declaration, or maintained that slavery was a positive good. We must recognize, however, that slavery next to the family was perhaps the oldest institution of civilized mankind. Its origin in the ancient world came with the discovery that it was more profitable to enslave an enemy defeated in war than to kill him. The ancient law of the ancient city may be seen in the Bible. When the Israelites conquered Jericho, they put to the sword everyone in the city—men and women, young and old, sheep, oxen, and asses. Only Rahab the harlot and her family were spared, since they had given shelter to the Israelite spies. Later, in the custom of ancient warfare, the males of a defeated people would all be killed, but the women and children would be carried into slavery. Eventually the entire population of a defeated people would be enslaved. Such are the steps in the human story. That defeat in war meant slavery was the rule for many thousands of years.