Mishkat al-Masabih
Mishkat al-Masabih 3422
Section 2
Arabic hadith text
وَعَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا اجْتَهَدَ فِي الْيَمِينِ قَالَ: «لَا وَالَّذِي نفس أَبُو الْقَاسِم بِيَدِهِ» . رَوَاهُ أَبُو دَاوُد
Translation
Abu Sa'id al-Khudri told that when God’s Messenger swore strongly he said, “No, by Him in whose hand is the soul of Abu Qasim.” Abu Dawud transmitted it.