One who assents or subsribes to the actions of a group or a party is as good as having committed the deed himself. A man who joins a sinful deed makes himself responsible for two-fold punishments, one for doing the deed and the other for assenting and subscribing to it.

Mola Ali (a.s) Ibn e Abu Talib (a.s)
Ref: Nahjul Balagha [ Saying # 154 ]