European colonists justified slavery on a number of grounds. Some argued that the institution was openly endorsed in the Bible. The first settlers were staunch Protestants who believed in the inerrancy of Scripture. And so if the Bible endorsed slavery—"Slaves, obey your earthly masters with respect and fear, and with sincerity of heart, just as you would obey Christ" (Ephesians 6:5–9)—then as far as the settlers were concerned, that was that. Slavery was seemingly divinely ordained, and so who were they to go against the will of God?
Widespread belief in the racial superiority of the white man was also an important factor in justifying slavery. The first American settlers, all of whom were white, regarded African slaves as "savages," uncivilized heathens from a mysterious continent in which all manner of strange, ungodly practices were carried out. As settlers didn't accept black Africans as their equals, they had no moral qualms about enslaving them. As far as they were concerned, this was a natural hierarchy, and they regarded slaves as subhuman.