(Imām Bukhārī narrates): 'Abdullāh ibn Maslamah narrated to us, from Imām Mālik, from Abī Hāzim, from Sahl ibn Sa'd, he narrated that:

the people were commanded that a person should place his right hand upon his left forearm in prayer.

Abū Hāzim said that Sahl attributed this saying only to the Prophet ﷺ. Ismā'īl said: This saying is attributed (to the Prophet ﷺ), and he did not say that Sahl attributed it.