Did Sheikh al-Islam Ibn Taymiyyah or others permit combining two prayers for one who prayed Maghrib and did not intend to combine until after concluding it, then prayed 'Isha before its time expired due to an excuse such as سلس (incontinence)?

Ibn Taymiyyah holds that combining two prayers at the time of the first does not require an intention (niyyah (definition)) or continuity (muwalat), because its meaning is to make their time one, and because stipulating such would contradict the concession. Furthermore, it has not been transmitted that the Prophet, peace and blessings be upon him, commanded the intention for combining prayers at 'Arafah; rather, he led them in the Dhuhr and 'Asr prayers without a prior intention. He also mentioned that the majority of scholars believe that neither the intention for shortening (qasr) nor for combining (jam') is a condition.

The majority of scholars, however, are of the opinion that the intention is a condition, either at the time of commencing the first prayer (ihram (definition) bi al-ula) or before concluding it (qabl salamihaha), and this opinion is more cautious. He believes that acting upon Ibn Taymiyyah's opinion is permissible out of necessity due to the ease and removal of hardship it offers.

As for combining prayers for one suffering from continuous ritual impurity (sahib al-sals), the majority of scholars do not consider it permissible, based on the authentic narration that the Prophet, peace and blessings be upon him, commanded the woman suffering from irregular bleeding (mustahadah) to perform ablution for every prayer, whereas Imam Ahmad permitted it.