(12) باب النَّهْىِ عَنِ التَّخَصُّرِ، فِي الصَّلاَةِ
It was narrated from Abu Hurairah that:
The Prophet (ﷺ) forbade praying with one's hands on one's waist. (ID)
Reference (ID): Sunan an-Nasa'i 890 (ID)
In-book reference (ID): Book 11, Hadith 15 (ID)
English translation (ID): Vol. 2, Book 11, Hadith 891 (ID)