The belief that slavery was necessary to maintain social order. Many white Southerners argued that slavery was necessary to prevent blacks from rising up and threatening white supremacy. They claimed that blacks were inherently violent and dangerous, and that slavery was the only way to keep them under control.
The belief that slavery was beneficial to blacks. Some white Southerners argued that slavery was actually beneficial to blacks, because it provided them with food, shelter, and protection. They claimed that blacks were better off as slaves than they would be if they were free.
These are just some of the arguments that were used by some Southerners to justify slavery. It is important to note that not all Southerners agreed with these arguments, and that many Southerners were opposed to slavery. However, these arguments were widely held and helped to shape the thinking of many white Southerners.