"Alqamah bin Wa'il told us that his father said: "I saw the Messenger of Allah ﷺ, when he was standing in prayer, holding his left hand with his right.'"  

رَأَيْتُ رَسُولَ اللَّهِ ﷺ إِذَا كَانَ قَائِمًا فِي الصَّلاَةِ قَبَضَ بِيَمِينِهِ عَلَى شِمَالِهِ