What is the ruling on sometimes delaying and combining prayers, and how can delayed prayers be made up, and what are the rulings concerning that, and are there simplified books for learning religious matters such as prayer, purification, and remembrance?

Neglecting prayer until its time has passed is a grave sin, greater than adultery, theft, drinking alcohol, and killing a soul. Ibn al-Qayyim reported a consensus on this matter, and one who commits this sin is exposed to Allah's punishment. Similarly, abandoning congregational prayer is an act of disobedience, and the Prophet, peace and blessings be upon him, intended to burn the houses of those who failed to attend it.

Regarding making up prayers, whoever sleeps through a prayer or forgets it should pray it when he remembers it. However, for one who intentionally abandons prayer, some scholars – such as Ibn Taymiyyah – held that making it up is not beneficial, while the majority view is that one is obliged to make it up along with repentance and seeking forgiveness.

One who intentionally abandons prayer should increase in supererogatory prayers, repentance, seeking forgiveness, and remorse. It is advisable to read beneficial books such as "Riyadh as-Salihin" and "Al-Kalim at-Tayyib (definition)," and the fatwas of scholars like Ibn Baz and Ibn Uthaymeen, and "Ash-Sharh al-Mumti'" by Ibn Uthaymeen, or concise jurisprudential books such as "Al-Mulakhkhas al-Fiqhi" or "Minhaj al-Muslim."