I forget the exact wording from Twain's AUTOBIOGRAPHY, but at one point he
recalls that no one in his youth
told him that slavery was wrong.  The evil was not preached in church and
those who needed assurance were shown Bible verses.

Can anyone note other historical or literary references pointing to the
church's use of the Bible to justify slavery?  Is there any other material
in the Twain canon elaborating on this point other than what is in Howard
Baetzhold and Joe McCullough's outstanding anthology of Twain's Biblical
writings?

Here's what I have on Biblical references:

"Priests (the Levites) were allowed to ownslaves, and allowed to buy them
from neighboring countries as inheirantences for their children. Outside of
occasional references to the seven-year "Jubilee," not until the time of the
Babylonian captivity is there a Biblical call to free slaves, and only then
Hebrew servants are mentioned (Jeremiah 34).  Even then, God instructs new
enslavement of those who opposed the Israelites, commanding that their
children be sold to the House of Judah (Joel 2).  After the Israelites
become dominant in Canaan, the victors put conquered cities to "forced
labor."  One pointed example occurs when
the non-threatening city of Jericho   is ravished, a relatively small city
estimated to have covered only seven acres.  When three tribal leaders hear
of the massacre, by trickery they obtain a vow for their people to not be
slaughtered.  Joshua is surprised they would stoop to such deceit to save
themselves, and instead enslaves them as "hewers of wood and drawers of
water."  Even Christ says nothing about the freeing of slaves but rather
that they should attempt to be like their masters.  Paul later echoes this
call, saying slaves must be obedient, respectful, and pleasing "with all
your heart" (Ephesians 6: 5-8; repeated in Colossians 3 and 4)."