الكافي- ط الاسلامية, volume 3, page 447

20. A number of our people have narrated from Ahmad ibn Muhammad from al-Husayn ibn Sa‘id from Hammad ibn ‘Isa from Mu‘awiyah ibn Wahab who has said the following: “I once said to abu ‘Abd Allah (a.s.), ‘A man of your followers, of their virtuous ones complained before me against sleep. He said that he wants to get up for the nightly optional Salah (prayer) but sleep overcomes him until it is morning. Sometimes he performs the compensatory prayer for a whole month of missed Salah (prayer) or two months and bears with its heaviness.’ He (the Imam) said, ‘It is the delight for his eyes, by Allah.’ He (the narrator) has said that he (the Imam) did not give him permission to perform his nightly optional Salah (prayer) in the beginning of the night, saying, ‘To do compensatory prayer for them during the day is better.’ I (the narrator) then said, ‘Of our virgin girls there are those who love good and people of goodness. They try to perform Salah (prayer) but sleep overcomes them, and perhaps they may perform the compensatory prayer for what is missed and perhaps face weakness in performing the compensatory prayer for what is missed, but she is able to perform in the beginning of the night. He (the Imam) granted them permission to perform Salah (prayer) in the beginning of the night if they feel weakness and lose performing the compensatory prayer for what is missed.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

21. Ahmad ibn Idris has narrated from Muhammad ibn ‘Abd al-Jabbar from Safwan from ibn Bukayr who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘A man who gets up in the end of the night to perform his nightly optional Salah (prayer), all of them at one time and goes away to sleep, is not very praiseworthy.”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.