I think it was the Biblical principle of freedom (Gal.5: 1) that spurred Christians to take the lead in abolishing slavery in England and the U.S. (nakedpastor.com)
The title refers to the 13th Amendment, which abolished slavery as well as involuntary servitude «except as a punishment for crime whereof the party shall have been duly convicted.» (timeout.com)
Webb believes that Scripture clearly points toward the ultimate ethic of abolishing slavery altogether. (rachelheldevans.com)