Authentic Supplication Number 110.

It is reported of the Messenger of Allah  that he said: “Two qualities, or attributes, no Muslim would mantain them except that he would enter Paradise, and they are easy yet few people mantain them: To make tasbeeh of Allah [for example saying Subhana ‘allahi(131)] after each salat ten times, to make tahmeed of Him [for example, saying Al-hamdu lil-lahi(132)] ten times, and to declare His greatness [for example saying ‘allahu akbaru (133)] ten times. That would add up to one hundred and fifty [merits, counting all five prayers] by the tongue, and one thousand five hundred in the balance. And to make takbeer 34 times when he has gone to bed, tahmeed 33 times, and tasbeeh 33 times. That would add up to one hundred by the tongue, and one thousand in the balance.

He said, for I have seen the Messenger of Allah  count them with his hand (134). They asked O’ Messenger of Allah! How is it that this is such an easy thing, yet those that practice it are so few? He said: “He comes to you – meaning shaytan when ready to sleep – and makes him fall asleep before saying [the above mentioned remembrance of Allah], and he comes to him iat prayer time and reminds him of things that he needs so as to make him hurry off before saying [the above mentioned remembrance of Allah].”

(131) Glory be to Allah.
(132) All praise be to Allah.
(133) Allah is greater [than all].
(134) Note that this is a reference to a single hand. Abu Dawood’s narration which is of sound ascription adds that “he would count them with his right hand”. Counting with both hands is thus inconsistent with the Sunnah. Example uses of the right hand are in offering people things, accepting things from others, shaking hands, eating, and drinking. Example uses of the left hand are in blowing one’s nose, holding something dirty, washing after use of the rest-room, and touching the private parts.

Abu Dawood, At-Tirmithi, and An-Nisa’ee. Al-Albani mentioned a report by Abu Dawood saying that the Prophet  used to count them with his right hand, that it was of sound ascription in his view, and that An-Nawawi said it was comely in his Al-Athkar. Al-Albani included this hadeeth in The Authentic of Good Sayings as #93.