The correct answer to this open question is the following.
Although there is no question posted and no reference attached, we can say that the above.mentioned quoted refers to the Battle of Fort Sumter, in Charleston, South Carolina, and represents the beginning of the American Civil War. The battle started on April 12, 1861, and ended one day after with a sounded victory for the Confederates, or more specifically, the militia of South Carolina.
The above-mentioned quote refers more specifically to the participation of abolitionists that aimed to end slavery in the southern territories and the later participation of African Americans in the Civil War, fighting for liberty.