21 Now there was a strict law among the people of the church, that there should not any man, belonging to the church, arise and persecute those that did not belong to the church, and that there should be no persecution among themselves.
22 Nevertheless, there were many among them who began to be proud, and began to contend warmly with their adversaries, even unto blows; yea, they would smite one another with their fists.
23 Now this was in the second year of the reign of Alma, and it was a cause of much affliction to the church; yea, it was the cause of much trial with the church.
24 For the hearts of many were hardened, and their names were blotted out, that they were remembered no more among the people of God. And also many withdrew themselves from among them.
(Alma 1:21-24)
Note who was permanently affected by the contention: not the victims of the violence, but the perpetrators. When we cause contention, it hardens our own hearts and affects us far more than it affects those we harm.
This is one of the great ironies of life: it harms the victim temporarily; it harms the perpetrator permanently unless they repent.