Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
ahmad-zuhd:439ʿAbdullāh > Bī > Ḥasan b. al-Rabīʿ > ʿAbthar Abū Zubayd

[Machine] Muhammad bin Al-Nadr disappeared from me for forty days, and I did not see him sleeping, neither during the night nor during the day.  

الزهد لأحمد:٤٣٩حَدَّثَنَا عَبْدُ اللَّهِ حَدَّثَنَا أبِي أَخْبَرَنَا حَسَنُ بْنُ الرَّبِيعِ حَدَّثَنِي عَبْثَرٌ أَبُو زُبَيْدٍ قَالَ

«اخْتَفَى عِنْدِي مُحَمَّدُ بْنُ النَّضْرِ أَرْبَعِينَ يَوْمًا فَمَا رَأَيْتُهُ نَائِمًا؛ لَيْلًا وَلَا نِهَارًا»