Al-Sheikh Al-Kuleini states in Al-Kafi Book: Abdellah bin Sinan reported from Imam Abou Abdellah (Pbuh) that he said: "For he who recites Al-Kafiroun and Al-Tawheed chapters before he goes to bed, Allah will write him a clearance from polytheism."
Ibn Babawaih states in Thawab Al-A'amal Book: Al-Hussein bin Abi Al-Alaa reported from Imam Abou Abdellah (Pbuh) that he said: "For he who recites Al-Kafiroun and Al-Tawheed chapters in a regular prayer, he and his parents are forgiven. If he was meant to be miserable, his name is erased from among the miserable and written among the happy. Allah will make him live happily, die as a martyr and be resurrected as a martyr."
Al-Tabrasi states in Majma' Al-Bayan Book: Obei reported that he said to the Messenger of Allah (Pbuhp): "I came to you so that you teach me something that I would say when I sleep." He (Pbuhp) said: "When you go to your bed recite Al-Kafiroun Chapter and sleep at its end for it is a clearance from polytheism."
Khawas Al-Quran Book: The Messenger of Allah (Pbuhp) said: "For he who recites this chapter Allah will reward him as he recited one quarter of Quran. Demons never harm him and he will be saved from the horror of Resurrection Day. He who recites it before sleep shall never be harmed by anything during his sleep so teach it to your boys. He who recites it at dawn fifteen time and asks for what he wants for his life in Donia and the Hereafter Allah will respond to him unless what he asked for is a sin."