What is the ruling on swearing by triple divorce unintentionally concerning a past event, if its truthfulness or falsehood is not evident?

If you uttered the divorce (talaq) without intending it, but it was a slip of the tongue, then nothing is incumbent upon you according to the majority of scholars. However, if you intended to pronounce it but did not intend for it to take effect, this will not benefit you, because an explicit divorce takes effect without intention. If you made the divorce conditional on your friend's fear, then if he explicitly states his fear, a triple divorce takes place according to the majority. If he explicitly states that he is not afraid, then nothing is incumbent upon you. If it is difficult to ascertain your friend's state, then nothing is incumbent upon you, because the breach of the oath is doubtful, and the default is the continuation of the marital bond. Divorce can be made conditional on a past or future event, and it takes effect upon the occurrence of the condition, according to the majority. However, Sheikh al-Islam Ibn Taymiyyah holds that it entails an expiation for an oath (kaffarat yamin) if divorce was not intended.