1. Srila Bhaktisiddhanta on deceitfulness

    If we put on the garb of a devotee and become busy with non-devotional activities, if we are absorbed in material enjoyment and that becomes a priority, or if we take the tridanda and want to kidnap Sita, like Ravana, then we are stabbing ourselves to death. We are doing something terrible in the name of hari-bhajana. If for millions of births we have some weakness, some bad habits, that is not so harmful. But if once we take to the path of deceitfulness – we pretend to be devotees but secretly engage in sinful enjoyment – then all troubles will remain with us. It is better to take birth among millions of other species, as a birth, or a beast or an insect.

    Srila Bhaktisiddhanta Sarasvati Prabhupada; from "Srila Prabhupader Upadesamrta"