A wrathful man stirreth up strife: but he that is slow to anger appeaseth strife. (Proverbs 15:18, KJV)
While the first shot was fired by the Confederates at Fort Sumter in South Carolina on April 12, 1861, it was the instigation of the Northern states that resulted in the start of the hostilities. Seven Southern states seceded from the Union (including SC) and Fort Sumter was under Union control prior to the start of the war. Abraham Lincoln sent supplies to Fort Sumter even though doing so would be considered an act of foreign aggression since the fort was in a Confederate State. When General P.G.T. Beauregard from the South issued an ultimatum to Union Major Robert Anderson to surrender the fort or else be attacked, Anderson refused to yield. This resulted in firing on the fort, thus marking the start of the war.