The Messenger of Allah ﷺ forbade a man to pray with his hands on his hips.
حدثنا معاوية قال حدثنا زائدة عن هشام بن حسان عن محمد بن سيرين
نهى رسول الله ﷺ أن يصلي الرجل مختصرا
Its isnad is sahih, Bukhari narrated it 3/88 no. 1220, in "leaning while standing in prayer," Fath al-Bari, and Muslim 1/387 no. 545, in Mosques, "the dislike of leaning in prayer." And Tirmidhi 1/222 no. 382, in Prayer, "what has been said about the prohibition of leaning." And Nasai in "the opening of prayer," "the prohibition of leaning," 2/127 no. 890.