Abdul-Rahman bin Abdul-Qari reported,
I went out with Umar bin Khattab during Ramadan to the mosque, and there were the people scattered in separate groups. A man would pray by himself, and another man would pray with a small group following his prayer.Umar said, "By Allah, I think it would be better if I gathered these people behind a single reciter."So he resolved on this and gathered them behind Ubayy bin Kaab.Then I went out with him on another night, and the people were praying with the prayer of their reciter.Umar said, "What an excellent innovation this is! But the one they sleep through is better than the one they stand for," meaning the latter part of the night, for the people were standing in prayer at its beginning.
Azami 4644
Sahihعن عبد الرحمن بن عبد القاري أنه قال
خرجت مع عمر بن الخطاب في رمضان إلى المسجد، فإذا الناس أوزاع متفرقون، يصلي الرجل لنفسه، ويصلي الرجل فيصلي بصلاته الرهط. فقال عمر: والله إني لأراني لو جمعت هؤلاء على قارئ واحد لكان أمثل، فجمعهم على أبي بن كعب قال: ثم خرجت معه ليلة أخرى والناس يصلون بصلاة قارئهم. فقال عمر: نعمت البدعة هذه! والتي تنامون عنها أفضل من التي تقومون يعني آخر الليل، وكان الناس يقومون أوله.
Malik narrated it in "Prayer in Ramadan" (3) from Ibn Shihab, from Urwa bin Zubayr, from Abdul-Rahman bin Abdul-Qari, and he related it. Bukhari narrated it in "Tarawih Prayer" (2010) through the route of Malik, with the same wording.As for Umar's saying 
, "What an excellent innovation this is," the word "innovation" here carries its linguistic meaning. In the technical sense of the Sharia, however, innovation stands in opposition to sunnah. Umar only praised it because it was not an innovation in the Sharia sense, but rather a sunnah, since the Prophet ﷺ had confirmed it by praying with those who prayed with him on some nights of Ramadan, even though he disliked doing so for them out of fear that it might be made obligatory upon them. When the Prophet ﷺ passed away, that concern was removed. For this reason Ibn Battal said, "Standing in prayer during Ramadan is a sunnah, because Umar only took it from an action of the Prophet ﷺ, and the Prophet ﷺ only left it out of fear that it would become obligatory." See Fath al-Bari (4/252).Most of the companions followed the practice of Umar bin Khattab in gathering the people behind a single reciter. It has likewise been reported from Ali bin Abu Talib that he used to command the people to stand in prayer during Ramadan, appointing an imam for the men and an imam for the women. Arfaja said, "He appointed me, so I led the women in prayer." This report, however, is daif.Abdul-Razzaq narrated it (5125, 7722) from Muhammad bin Umara, from Umar Thaqafi, from Arfaja, that Ali used to command the people, and he related it. In the second instance, he said, Abu Umaya Thaqafi, from Arfaja. Bayhaqi narrated it in "The Merits of Times" (125) through another route, from Abu Abdullah Thaqafi, who said, Arfaja narrated to us, from Ali.This Umar is Umar bin Abdullah bin Yaala bin Murra Thaqafi, who is daif. Daraqutni said, "Discarded (matruk)." He is among the men listed in "Tahdheeb," except that his kunya, whether Abu Umaya or Abu Abdullah, is not mentioned there. So take note.