Early nineteenth century Americans did not view sin as a metaphysical abstraction. Religious leaders taught that sin was concrete. High living, moral indifference, and preoccupation with worldly and commercial matters--all these were denounced as manifestations of human depravity. After Aaron Burr killed Alexander Hamilton in a duel, a growing number of reformers denounced duelling as a sin, a relic of a more barbaric stage in human history. In the future, later reformers would not only denounce drinking and slavery as capital sins, but would repudiate all forms of force and violence.
In a letter to his son, William Ellery condemns duelling.
You are about to write a composition on duelling, and I...wish that I could assist you composing those final lines....
Duelling is a mode of settling certain points of honour, as they are called, by single combat.... It was introduced into Europe at a barbarious period, a period when property was not decided by judicial combat, when it was absurdly imagined that the Deity would always give victory in favor of right. Both these practices [are inconsistent] with the Christian religion.... The party who killed his adversary...is...guilty of murder, & expressly forbidden by the eighth commandment in the Decalogue [the Ten Commandments] and sound reason can never admit what God has prohibited & Judicial combats have long since been pushed aside and for the sake of religion, reason and humanity, the infamous practice of duelling out to be reprobated with universal contempt.