salat, the daily ritual prayer enjoined upon all Muslims as one of the five Pillars of Islam (arkān al-Islām). There is disagreement among Islamic scholars as to whether some passages about prayer in the Muslim sacred scripture, the Qurʾān, are actually references to the salat. Within Muhammad’s lifetime, five obligatory prayers, each preceded by ablution, were observed: ṣalāt al-fajr (dawn), al-ẓuhr (midday), al-ʿaṣr (afternoon), al-maghrib (sunset), and al-ʿishāʾ (evening). Under such special circumstances as illness, a journey, or war, a modification or limited postponement of these salats is allowed.
Though individual performance of salat is permissible and can be offered in any clean space at home or at work, collective worship in the mosque has special merit. With their faces turned in the direction of the shrine of the Kaaba in Mecca, the worshippers align themselves in parallel rows behind the imam, or prayer leader, who directs them as they execute the rakʿahs (physical postures coupled with Qurʾānic recitations).
On Fridays, instead of the prayer just after noon, a congregational prayer (ṣalāt al-jumʿah) is offered; it includes two sermons (khutbah) delivered from the pulpit. Special congregational prayers are offered in the middle of the morning on the two festival days (ʿīds), one immediately following the month of fasting, Ramadan, and the other following the pilgrimage, or hajj. Although not obligatory, individual devotional prayers, especially during the night, are emphasized and are a common practice among pious Muslims.