“On the American side, the Negro saw limited military service until the war dragged on into its third year. This negative attitude toward enlisting the Colored man, sprang from a reluctance to deprive the slavemaster of his chattel slave, and from the fear of putting guns in the hands of a class of persons most of whom were not free. In the main, the Negro was thought of as a servile laborer, rather than a potential warrior. But when manpower needs became acute, whether in the volunteer forces, the militia, or the continental troops, fears were put into the background and the Negro was mustered in.”
Quarles was an African-American historian, scholar, educator, and writer; his books include "The Negro in the American Revolution" (1961), from which this quote is taken.