The Prophet (ﷺ) said, "Whoever fasted the month of Ramadan out of sincere Faith (i.e. belief) and hoping for a reward from Allah, then all his past sins will be forgiven, and whoever stood for the prayers in the night of Qadr out of sincere Faith and hoping for a reward from Allah, then all his previous sins will be forgiven ."
Sahih al-Bukhari Book 32, Hadith 1
← Previous Hadith 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."

Sahih al-Bukhari Book 31, Hadith 6 Next Hadith → Some men amongst the companions of the Prophet (ﷺ) were shown in their dreams that the night of Qadr was in the last seven nights of Ramadan. Allah's Messenger (ﷺ) said, "It seems that all your dreams agree that (the Night of Qadr) is in the last seven nights, and whoever wants to search for it (i.e. the Night of Qadr) should search in the last seven (nights of Ramadan).

Sahih al-Bukhari Book 32, Hadith 2