The Prophet (may Allah's peace and blessings be upon him) forbade praying with one's hands on one's waist
Authentic hadithعن أبي هريرة رضي الله عنه ، قال: «نهى النبي صلى الله عليه وسلم أن يصلي الرَّجُلُ مُخْتَصِرًا».
Abu Hurayrah (may Allah be pleased with him) reported: The Prophet (may Allah's peace and blessings be upon him) forbade praying with one's hands on one's waist.
Explanation
The Prophet (may Allah's peace and blessings be upon him) forbade praying while putting the hands on the waist.
Source · Narrated by Bukhari & Muslim
From the Hadith Encyclopedia (hadeethenc.com).