Is rinsing the mouth obligatory according to the four schools of thought and the scholars of Ahlus-Sunnah after waking up from sleep, or is it merely recommended by them?

In the Hanbali school, istinsthaq (sniffing water into the nose) upon waking from sleep is not obligatory. They obligate washing the hands three times before immersing them in a vessel for someone who has woken up from night sleep that invalidates wudu' (ablution). Madmadah (rinsing the mouth) and istinshaq are obligatory for them during wudu' and ghusl (ritual bath).

As for Ibn Hazm, he obligates istinsthaq and istinthar (expelling water from the nose) three times upon waking from sleep, whether at night or during the day, due to a hadith mentioned regarding it. He believes that whoever does not do this, their prayer and wudu' are not valid.

None of the scholars assert the obligation of madmadah for someone who has woken up from sleep. Rather, the Hanbalis obligate it in wudu', contrary to the majority of scholars. The fatwa issued is based on the opinion of the majority.