Sunan Ibn Majah, Chapter: The Chapters of Establishing the Prayer and the Sunnah Regarding Them

"The Messenger of Allah (saw) said: 'There are two characteristics which no Muslim man acquires but he will enter Paradise. They are easy but those who do them are few. At the end of every prayer he should glorify Allah (by saying Subhan Allah) ten times, extol Him (by saying Allahu Akbar) ten times, and praise Him (by saying Al-Hamdu Lillah) ten times.' I saw the Messenger of Allah (saw) counting them on his hand. 'That is one hundred and fifty (after all the prayers of the day) on the tongue, and one thousand and five hundred on the Scale. And when he goes to his bed, let him glorify Allah and praise Him and extol Him one hundred times. That will be one hundred on the tongue and one thousand on the Scale. Who among you does two thousand and five hundred evil actions in one day?' They said: 'Who would not be keen to do that?' He said: 'But the Shaitan comes to anyone of you while he is performing prayer and says: 'Remember such and such, remember such and such," until the person becomes distracted and does not understand (what he is saying). And he comes to him when he is in his bed, and makes him sleepy such that he sleeps.'" (Hasan)