Robert E. Lee letter dated December 27, 1856: "...There are few, I believe, in this enlightened age, who will not acknowledge that slavery as an institution is a moral and political evil. It is idle to expatiate on its disadvantages. I think it is a greater evil to the white than to the colored race. While my feelings are strongly enlisted in behalf of the latter, my sympathies are more deeply engaged for the former. The blacks are immeasurably better off here than in Africa, morally, physically, and socially. The painful discipline they are undergoing is necessary for their further instruction as a race, and will prepare them, I hope, for better things. How long their servitude may be necessary is known and ordered by a merciful Providence. Their emancipation will sooner result from the mild and melting influences of Christianity than from the storm and tempest of fiery controversy. This influence, though slow, is sure. The doctrines and miracles of our Saviour have required nearly two thousand years to convert but a small portion of the human race, and even among Christian nations what gross errors still exist! While we see the course of the final abolition of human slavery is still onward, and give it the aid of our prayers, let us leave the progress as well as the results in the hands of Him who, chooses to work by slow influences, and with whom a thousand years are but as a single day. Although the abolitionist must know this, must know that he has neither the right not the power of operating, except by moral means; that to benefit the slave he must not excite angry feelings in the master..."In other words, black folks are better off in bondage than they were free in Africa, and regardless, slavery will be around until Providence decides, and who are we to second guess that? And the only reason the masters beat their slaves is because of the abolitionists.
Very late in the war - January 1865 - Lee wrote the following on that subject:
"Considering the relation of master and slave, controlled by humane laws and influenced by Christianity and an enlightened public sentiment, as the best that can exist between the white and black races while intermingled as at present in this country, I would deprecate any sudden disturbance of that relation unless it be necessary to avert a greater calamity to both. I should therefore prefer to rely upon our white population to preserve the ratio between our forces and those of the enemy, which experience has shown to be safe. But in view of the preparations of our enemies, it is our duty to provide for continued war and not for a battle or a campaign, and I fear that we cannot accomplish this without overtaxing the capacity of our white population. "
Lee's opposition to slavery was tepid at best.