He said that God wanted him to fight slavery by invading Virginia with a military force.
VOA: special.2009.06.25
Muslim rulers, from the Abbasids in the eighth century to the Mamluk sultanate in Egypt and the Ottomans, developed the institution of militaryslavery to lessen nepotism and the internal conflicts created by tribal loyalties.
The Civil War confronted Americans with an enormous task, one quite different from saving or dividing the nation, ending or maintaining slavery, or winning the military conflict the demands we customarily understand to have been made of the Civil War generation.