Mishkat al-Masabih 1003
What may not be done during Prayer and what is permitted - Section 2
وَعَنِ ابْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «الِاخْتِصَارُ فِي الصَّلَاةِ رَاحَةُ أَهْلِ النَّارِ». رَوَاهُ فِي شرح السّنة
Translation
Ibn ‘Umar reported God’s Messenger as saying, “Resting the hands on the waist in prayer is the comfort of those who go to hell.” [Baghawi] transmitted it in Sharh as-sunna.
Grades by grader
No grade is recorded for this wording.