I heard Allah's Messenger (ﷺ) saying regarding Ramadan, "Whoever prayed at night in it (the month of Ramadan) out of sincere Faith and hoping for a reward from Allah, then all his previous sins will be forgiven."

Allah's Messenger (ﷺ) said, "Whoever prayed at night the whole month of Ramadan out of sincere Faith and hoping for a reward from Allah, then all his previous sins will be forgiven." Ibn Shihab (a sub-narrator) said, "Allah's Messenger (ﷺ) died and the people continued observing that (i.e. Nawafil offered individually, not in congregation), and it remained as it was during the Caliphate of Abu Bakr and in the early days of 'Umar's Caliphate."

'Abdur Rahman bin 'Abdul Qari said,

"I went out in the company of 'Umar bin Al-Khattab one night in Ramadan to the mosque and found the people praying in different groups. A man praying alone or a man praying with a little group behind him. So, 'Umar said, 'In my opinion I would better collect these (people) under the leadership of one Qari (Reciter) (i.e. let them pray in congregation!)'. So, he made up his mind to congregate them behind Ubai bin Ka'b. Then on another night I went again in his company and the people were praying behind their reciter. On that, 'Umar remarked, 'What an excellent Bid'a (i.e. innovation in religion) this is; but the prayer which they do not perform, but sleep at its time is better than the one they are offering.' He meant the prayer in the last part of the night. (In those days) people used to pray in the early part of the night."

(the wife of the Prophet) Allah's Messenger (ﷺ) used to pray (at night) in Ramadan.

That he was informed by `Aisha, "Allah's Messenger (ﷺ) went out in the middle of the night and prayed in the mosque and some men prayed behind him. In the morning, the people spoke about it and then a large number of them gathered and prayed behind him (on the second night). In the next morning the people again talked about it and on the third night the mosque was full with a large number of people. Allah's Messenger (ﷺ) came out and the people prayed behind him. On the fourth night the Mosque was overwhelmed with people and could not accommodate them, but the Prophet (ﷺ) came out (only) for the morning prayer. When the morning prayer was finished he recited Tashah-hud and (addressing the people) said, "Amma ba'du, your presence was not hidden from me but I was afraid lest the night prayer (Qiyam) should be enjoined on you and you might not be able to carry it on." So, Allah's Apostle died and the situation remained like that (i.e. people prayed individually). "

that he asked `Aisha "How was the prayer of Allah's Messenger (ﷺ) in Ramadan?" She replied, "He did not pray more than eleven rak`at in Ramadan or in any other month. He used to pray four rak`at ---- let alone their beauty and length----and then he would pray four ----let alone their beauty and length ---- and then he would pray three rak`at (witr)." She added, "I asked, 'O Allah's Messenger (ﷺ)! Do you sleep before praying the witr?' He replied, 'O `Aisha! My eyes sleep but my heart does not sleep."