Abu hurairah said that the Messenger of Allah (May peace be upon him) forbade putting hands on the waist during prayer. Abu Dawud said; The word Ikhtisar means to put one’s hands on one’s waist.
نَهَى رَسُولُ اللَّهِ ﷺ عَنْ الاِخْتِصَارِ فِي الصَّلاَةِ