How did John Brown's raid effect the Civil War?

John Brown gathered white allies and free blacks and raided a government arsenal in Harpers Ferry, Virginia. His hopes that other slaves would join in the revolt and procure weapons to arm southern slaves was short-lived. After he captured the arsenal, he was surrounded and forced to surrender. He was tried, found guilty of treason, and executed. This raid caused Southern slave owners to militarize in preparation for future raids.