Where the Hands should be placed in Prayer
Question :
Is placing the right hand on the left hand over the chest a practice of the Prophet or not?
Answer:
It is from the Sunnah to place the right hand on the left forearm, or on the wrist, or on the left hand over the chest during the recitation while standing, and also while standing after straightening up from the bowing position, until one goes down for prostration. This is the guidance of the Messenger of Allah and his practical Sunnah. And may peace and blessings be upon our Prophet, Muhammad and upon his family and Companions.
Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 2 Page 258