Abu Huraira reported Allah's Messenger (ﷺ) as saying
He who observed prayer at night during Ramadan, because of faith and seeking his reward from Allah, his previous sins would be forgiven.
Abu Huraira reported
The Messenger of Allah (ﷺ) used to exhort (his Companions) to pray (at night) during Ramadan without commanding them to observe it as an obligatory act, and say: He who observed the night prayer in Ramadan because of faith and seeking his reward (from Allah), all his previous sins would be forgiven. When Allah's Messenger (ﷺ) died, this was the practice, and it continued thus during Abu Bakr's caliphate and the early part of 'Umar's caliphate.
Abu Huraira reported Allah's Messenger (ﷺ) as saying
He who observed the fasts of Ramadan with faith and seeking reward (from Allah), all his previous sins would be forgiven, and he who observed prayer on Lailat-ul- Qadr with faith and seeking reward (from Allah), all his previous sins would be forgiven.
Abu Huraira reported Allah's Apostle (ﷺ) as saying
He who prayed on the Lailat-ul-Qadr (the Majestic Night) knowing that it is (the same night). I (believe) that he (the Prophet also) said: (He who does) it with faith and seeking reward (from Allah), his sins would be forgiven.
'A'isha reported that the Messenger of Allah (ﷺ) prayed one night in the mosque and people also prayed along with him. He then prayed on the following night and there were many persons. Then on the third or fourth night (many people) gathered there, but the Messenger of Allah (ﷺ) did not come out to them (for leading the Tarawih prayer). When it was morning he said
I saw what you were doing, but I desisted to come to you (and lead the prayer) for I feared that this prayer might become obligatory for you. (He the narrator) said: It was the month of Ramadan.
'A'isha reported
The Messenger of Allah (ﷺ) came out during the night and observed prayer in the mosque and some of the people prayed along with him. When it was morning the people talked about this and so a large number of people gathered there. The Messenger of Allah (ﷺ) went out for the second night, and they (the people) prayed along with him. When it was morning the people began to talk about it. So the mosque thronged with people on the third night. He (the Holy Prophet) came out and they prayed along with him. When it was the fourth night, the mosque was filled to its utmost capacity but the Messenger of Allah (ﷺ) did not come out. Some persons among then cried:" Prayer." But the Messenger of Allah (ﷺ) did not come to them till he came out for the morning prayer. When he had completed the morning prayer, he turned his face to the people and recited Tashahhud (I bear testi- mony that there is no god but Allah and I bear testimony that Muhammad is His Messen- ger) and then said: Your affair was not hidden from me in the night, but I was afraid that (my observing prayer continuously) might make the night prayer obligatory for you and you might be unable to perform it.
Zirr (b. Hubaish) reported
I heard from Ubayy b. Ka'b a statement made by 'Abdullah b. Mas'ud in which he said: He who gets up for prayer (every night) during the year will hit upon Lailat-ul-Qadr. Ubayy said: By Allah I there is no god but He, that (Lailat-ul-Qadr) is in Ramadhan (He swore without reservation: ) By Allah, I know the night; it is the night on which the Messenger of Allah (ﷺ) commanded us to pray. It is that which precedes the morning of twenty-seventy and its indication is that the sun rises bright on that day without rays.
Ubayy b Ka'b reported
By Allah, I know about Lailat-ul Qadr and I know it fully well that it is the twenty-seventh night (during Ramadan) on which the Messenger of Allah (ﷺ) commanded us to observe prayer. (Shu'ba was in doubt about these words:" the night on which the Messenger of Allah [may peace be upon him] commanded us to observe the prayer." This has been transmitted to me by a friend of mine.)
Shu'ba reported this hadith with the same chain of transmitters, but he made no mention that Shu'ba was in doubt and what follows subsequently.