The Prophet (pbuh) stated the following: "The previous sins of a person who revives (prays and worships in) Ramadan by believing and expecting the reward from Allah will be forgiven." (Bukhari, Iman, 25, 27; Muslim, Musafirin, 173, 176; Ibn Majah, Iqamatu's-Sala, 173; Tirmidhi, Sawm, 83)

An-Nawawi, a hadith scholar says that Hazrat Muhammad (pbuh) did not render it wajib to revive Ramadan for his Companions but that he encouraged them to revive it; he adds that Islamic scholars agree that it is mandub to revive Ramadan. An-Nawawi says, "Ramadan is regarded to have been revived by performing tarawih prayers." From this point of view, the word of Hazrat Muhammad (pbuh),  “a person who revives Ramadan" should be understood as, "a person who revives Ramadan by performing prayers at night"(an-Nawawi, al-Minhaj, 1924, VI, 39, ff)

As a matter of fact, in a hadith reported by Abdurrahman b. Awf, Hazrat Muhammad (pbuh) says, "Allah definitely rendered fasting in Ramadan fard. I rendered reviving Ramadan nights sunnah. A person who revives Ramadan by fasting during the day and performing prayers at night believing and expecting the reward from Allah will be freed from his sins as if he has been newly born." (Ibn Majah, Iqamatu's-Sala, 173; Ibn Hanbal, I, 191, 195).

Hazrat Prophet (pbuh) led the prayer on a Ramadan night. Abu Dharr (may Allah be pleased with him) said, "O Messenger of Allah! Please lead us prayers for the rest of the night, too." Hazrat Prophet answered, "To perform the prayer together with the imam until he finishes the prayer is equal to reviving the whole night." (Abu Dawud, Salah 318; Tirmidhi, Sawm 81; Ibn Majah, Iqamatu's-Sala 173.)

It is agreed unanimously that what is meant by the phrase "to revive the night in Ramadan" is performing tarawih prayer. (Ayni, Umdatu'l-Qari, 9/198; Shirbini, al-Iqna, 1/117)