Shamelessly quoted from: http://www.samharris.org/forum/viewtopic.php?t=5717&start=568
"Yes, God allowed slavery - allowed people to live in the presence of what they had created. But in the grand scheme of things that is akin to getting a skinned knee as a child.(boggle!) I fully realize that this may offend you. But for a moment imagine eternity - forever in the presence of the absolute God. Look at it from God's perspective. We endure "light affliction" now, but in the process we learn the consequences of our actions, and more importantly, learn to trust, commune with, and obey God (whose commands are not grievous). Even the horrors of the Holocaust (light affliction!?!?) would fade from memory in the eternal presence of God. Our own questioning of his goodness will seem ridiculous. Before you get offended at this thought, just use the powers of imagination that your creator gave you and consider eternity with an infinitely wise, powerful and good God."
So, a "benevolent omnipotent, omniscient, omnipresent being" (BOOOB) allowed (and through divinely inspired biblical behavioural instruction, endorsed) slavery. We're talking generationally inherited "property-status" for living, breathing, thinking, caring people, (yup - the complete removal of personal autonomy) with instructions that beating them near unto death (but not to death - Exodus 20:21) is a-ok with the big-kahuna in the clouds.
Lets take this fellow at his word. Lets pretend for a moment that spending eternity (a difficult concept) at the side of the BOOOB will make all suffering trivial in comparison. How does this change the ethical and moral implications that the BOOOB turned a blind-eye to the suffering of uncountable people? How can any sane person create a plausible justification for this social personal cruelty contained within the OT?
(With an intellectual nod that this "justified" conceptualization all falls apart if the veracity of the BOOOB is not reasonably demonstrated.)
Further, if the BOOOB is simply a construct, then there is absolutely no ethical or moral justification for slavery - whether it have biblical endorsement or not.
Does this "justification" function as a compartment into which the aforementioned suffering (Slavery, Holocaust - quoted above) gets shoved into a shoebox in the back of the mind's closet and forgotten until rapture(tm)?