All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The hadeeths of placing the hands on the chest is proven through many narrations, one of which is the hadeeth reported in Saheeh al-Bukhari No. 740. Narrated Sahl ibn Sa'd : The people were ordered to place the right hand on the left forearm in the prayer. Abu Hazim said: I only know that this is attributed to the Prophet, sallallaahu`alayhi wa sallam.
And the hadeeth reported in Saheeh Muslim No. 401 which was narrated by Waa’il ibn Hajar that he saw the Prophet, sallallaahu`alayhi wa sallam, raise his hands when he started to pray and say Takbeer, and according to Hammam he raised his hands to the level of his ears. Then he wrapped his hands in his garment, putting his right hand on his left.
It was reported that Ibn ‘Abbas said: I heard the Messenger of Allah, sallallaahu`alayhi wa sallam, saying: “We Prophets have been commanded to hasten the breaking of our fast and to delay our suhoor, and to put our right hands over our left when praying.” (Reported by Ibn Hibban in his Saheeh. No. 885).
Abu Dawood reported (Hadeeth No. 750) from Tawus that he said: The Messenger of Allah, sallallaahu`alayhi wa sallam, used to place his right hand on his left hand, then he folded them strictly on his chest when praying. It is a mursal hadeeth but its men are thiqaat (trustworthy).Al-Albani supported it with what was reported in Musnad Ahmed, No. 21967 from Kabeesah ibn Hulb, from his father, who said: “I saw the Messenger of Allah, sallallaahu`alayhi wa sallam, turn (to leave) from his right and from his left. And he added, “he would place this on his chest.”
Allah knows best.