Does one who says, "By the prohibition of my religion" become an unbeliever merely by uttering the oath, or if he breaks it, or does he not become an unbeliever in either case if he does not intend what he says?

Prohibiting anyone other than the wife is an idle utterance (laghw) and has no consequences. The phrase "I prohibit by my religion" (علي الحرام من ديني) commonly means, "What is lawful for me is unlawful" (الحلال علي حرام). Scholars have differed regarding the ruling on prohibiting what is lawful. The Malikis held that it is an idle utterance except when it pertains to the wife, in which case a divorce occurs. The Hanafis and those who agreed with them maintained that an expiation for an oath (kaffarat yamin) is obligatory. The Hanbalis were of the view that an expiation for zihar (kaffarat zihar) is obligatory, or divorce if that was the intention. If the intention behind the statement was an idle utterance and not a deliberate intention, then no consequences follow.