The Commandments and moral life · Question 8
If I didn't do the bad thing myself, am I responsible for nothing?

The question: “If I just watched a friend being bullied, or only laughed along in the group chat, that's not on me, right?”
The Church's answer: Sin is a personal act, but a person can also share responsibility by cooperating in someone else's sin. That happens by freely taking part in an evil, by ordering or advising it, by praising or approving it, by staying silent when you have a duty to stop it or report it, and by shielding whoever did it. Passing an insult along online and egging bullying on with a ‘like’ affects real people and a real community too. Not having started it yourself doesn't make all the responsibility disappear.
Even so, no one is required to stop every evil single-handed. A child especially can end up in far greater danger by confronting a dangerous aggressor directly. Get somewhere safe, tell a responsible adult and a protection agency, and don't stay in danger trying to gather more evidence. Repeated choices by individuals can build a ‘structure of sin’ — a school that tolerates bullying, an organization that demands dishonesty — so rules, oversight, and reporting systems have to change along with people's repentance.
If they press further: “Is a bystander who said nothing just as responsible as the one who did it?” — roles, freedom, and duties differ, so responsibility isn't automatically the same either. Weigh the fear, the age, and whether stopping it was actually possible — then take part in what you can do safely now: reporting it, supporting the victim, and putting a stop to a false rumor.
In one sentence: “Even if you didn't start the evil, responsibility can arise when you freely help it along or egg it on, or look away when you ought to stop it. Don't face danger alone — take part in safe reporting and in protecting the victim.”