وَعَنِ ابْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «الِاخْتِصَارُ فِي الصَّلَاةِ رَاحَةُ أَهْلِ النَّارِ» . رَوَاهُ فِي شرح السّنة
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.”
transmitted it in Sharh as-sunna.