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.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
bayhaqi:5609 – Abū Saʿīd b. Abū ʿAmr > Abū al-ʿAbbās al-Aṣam > al-Rabīʿ > al-Shāfiʿī > al-Thiqah > Sulaymān b. Mūsá

[Machine] "O People of the Water,

When you receive this letter, collect yourselves when you reach forty (days)"  

البيهقي:٥٦٠٩ – وَأَخْبَرَنَا أَبُو سَعِيدِ بْنُ أَبِي عَمْرٍو ثنا أَبُو الْعَبَّاسِ الْأَصَمُّ أنبأ الرَّبِيعُ أنبأ الشَّافِعِيُّ قَالَ وَأَخْبَرَنِي الثِّقَةُ عَنْ سُلَيْمَانَ بْنِ مُوسَى

أَنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ كَتَبَ إِلَى أَهْلِ الْمِيَاهِ فِيمَا بَيْنَ الشَّامِ إِلَى مَكَّةَ جَمِّعُوا إِذَا بَلَغْتُمْ أَرْبَعِينَ