St John Vianney winning round his congregation:

I am going to explain to you, my dear brethren, what is understood by swearing, blasphemy, profanities, imprecations and curses. Try to sleep well during this period so that when the day of judgment comes, you will be found to have committed this evil without knowing what you were doing – though, of course, you will be damned, because your ignorance will be all your own fault (From ‘All that you say over and above these is of evil’ in ‘The Sermons of the CurĂ© of Ars’)