What is the established number of Rak'ahs for Tarawih prayer?
Chapter on the Times When Prayer is Prohibited
Al-Mughni
Book of Prayer
Primary text
The preferred number of Rak'ahs for the Tarawih prayer, according to Abu Abdullah (Imam Ahmad), is twenty Rak'ahs. This view is also held by Sufyan al-Thawri, Abu Hanifa, and Al-Shafi'i. The evidence supporting this number includes the practice of Umar ibn al-Khattab when he gathered the people behind Ubayy ibn Ka'b, who led them in twenty Rak'ahs for twenty nights. Furthermore, it is narrated that Umar commanded a man to lead the people in twenty Rak'ahs during Ramadan, and this practice reached a level of consensus among the Companions during his time.
Supporting text
Imam Malik stated the number to be thirty-six Rak'ahs, grounding his opinion on the established practice ('al-amr al-qadim') of the people of Medina, citing reports suggesting practices involving forty-one Rak'ahs with five Witr Rak'ahs. However, the reports supporting the Medinan practice are weak, and even if established, the action agreed upon by Umar and the Companions takes precedence. Some scholars suggest the Medinan practice arose from their desire to equalize their worship with the people of Mecca, who would perform Tawaf (circumambulation) seven times between every two sets of Tarawih prayers, dedicating four Rak'ahs for each circuit.