Sunan Abi Dawud, Book 1, Hadith 46 (USC-MSA)

Narrated Abu Hurayrah : (the Prophet, sal Allaahu alayhi wa sallam ) as saying : Were it not that I might oeverburdern the believers, I would order them to delay the night ('isha ) prayer and use the tooth-stick at the time of every prayer.

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، عَنْ سُفْيَانَ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، يَرْفَعُهُ قَالَ ‏ "‏ لَوْلاَ أَنْ أَشُقَّ، عَلَى الْمُؤْمِنِينَ لأَمَرْتُهُمْ بِتَأْخِيرِ الْعِشَاءِ وَبِالسِّوَاكِ عِنْدَ كُلِّ صَلاَةٍ ‏" ‏ ‏.‏

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also referenced under: Hadith 46 (DarusSalam) & Hadith 46 (Hasan)