'Aishah (May Allah be pleased with her) reported:
The Messenger of Allah (ﷺ) used to strive more in worship during Ramadan than he strove in any other time of the year; and he would devote himself more (in the worship of Allah) in the last ten nights of Ramadan than he strove in earlier part of the month.[Muslim]. (RU)
App reference (RU): Book 9, Hadith 204 (RU)
Arabic/English book reference (RU): Book 9, Hadith 1194 (RU)