• 1 - Prefatory Note on the Recommendation of Performing Tarawih in Congregation

Nowadays no layperson who adheres to the Sunnah doubts the legitimacy of offering the night prayer in congregation during Ramadan—the prayer commonly known as Tarawih—for three reasons:

A – his (peace and blessings be upon him) tacit approval of holding it in congregation;
B – his actually leading it himself;
C – his clarification of its merit.

As for the first—his tacit approval—it is demonstrated by the ḥadith of Thalabah ibn Abī Mālik al-Quraẓī, who said:

• 1 (hasan)
  The Messenger of Allah (peace and blessings be upon him) came out one night in Ramadan and saw some people praying in a corner of the mosque. He asked, “What are these people doing?” Someone replied, “Messenger of Allah, they are people who do not have Quran with them; Ubayy ibn Kaʿb is reciting and they are praying following his recitation.” He said, “They have done well,” or, “They have acted correctly,” and he expressed no disapproval of their action.

Narrated by al-Bayhaqī (2 / 495), who said, “This is a hasan mursal report.”

I say: It has also been transmitted with a connected chain through another route from Abū Hurayrah, with an isnād that is sound enough for corroboration. It was recorded by Ibn Naṣr in Qiyām al-Layl (p. 20), Abū Dāwūd (1 / 217), and al-Bayhaqī.⦗10⦘