Timed acts of worship are of four kinds:
Daily acts of worship
Weekly acts of worship
Monthly acts of worship
Yearly, or seasonal, acts of worship
The course of worship, expounded by the Ahl al-Bayt (‘a), has its origin in both the obligatory and recommended devotional acts determined by Islam in its code of law from which further actions branch out. The daily obligatory and supererogatory prayers, the weekly congregational Friday prayers, the obligatory fasting, the ritual Hajj Pilgrimage, and the recommended three-day fasting done every month are all indicative of the all-inclusiveness of this system.
To a certain extent and at a certain level, such all-inclusiveness is compulsory or semi-compulsory, while at another level, it gives man the opportunity to worship the Lord and attain self-perfection through these devotional acts within a wisely planned strategy of education, self-purification, and self-refinement.
The classification of these devotional acts also shows the profundity, accuracy, and perfection of this course delivered by the Ahl al-Bayt (‘a), and their attention towards the building of a virtuous community through the acts of worship and this course in particular.
This course comprises various acts such as prayers, fasting, pilgrimage (including the ritual major and minor Hajj and visiting the tombs of holy personalities), struggling against enemies, supplications, litanies, recitation of the Holy Qur'an, almsgiving, building good relations with others, doing charitable acts, seeking knowledge, and other obligatory and recommended devotional acts.