Sunan Abi Dawud 759
سنن أبي داود#759SahihNarrated Tawus: The Messenger of Allah (ﷺ) used to place his right hand on his left hand, then he folded them strictly on his chest in prayer
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Zubair Ali ZaiSahih
In-book reference: 2:369