Tahdhīb al-Aḥkām 3, record 214 of the digital edition

Translation

Al-Husayn ibn Said, from al-Hasan, from Zurah, from Sama’ah ibn Mihran, who said: I asked Imam (a.s) about the Month of Ramadan how much is to be prayed within it? Imam (a.s) said: “As is prayed in other months, except that (month of) Ramadan has over the rest of the months, a virtue which makes it befitting for the servant to increase in his supererogatory prayers. So if he wishes and is able to do so, let him increase during the first twenty nights of the month, each night twenty rak’ahs in addition to what he would normally pray before that. From these twenty, twelve rak’ahs are between Maghrib and Atamah (Isha), and eight rak’ahs after Atamah (Isha). Then he should pray the Night Prayer (salat al-layl), which he would pray before that eight rak’ahs, and the Witr, which is three rak’ahs; two rak’ahs in which he gives salam after them, then he stands and prays one rak’ah in which he recites qunut, this is Witr. Then he prays the two rak’ahs of Fajr when the dawn breaks these are thirteen rak’ahs. Then when there remains from the Month of Ramadan ten nights, then let him pray thirty rak’ahs each night, in addition to these thirteen rak’ahs. He should pray twenty-two rak’ahs between Maghrib and Isha, and eight rak’ahs after Atamah (Isha). Then after the Night Prayer (salat al-layl), let him pray thirteen rak’ahs as I have described to you. And on the night of the twenty-first and the twenty-third, let him pray on each of them, if he is able to do so, one hundred rak’ahs, in addition to these thirteen rak’ahs. And let him remain awake through both nights until morning, for it is recommended that they be spent in prayer, supplication, and humble entreaty. For it is hoped that Laylat al-Qadr is in one of them (the night of twenty-first or twenty-third).”

Translation: Haydar Ali Shaykh ibn Muhammad — published with the edition, reproduced verbatim.