Our beloved Prophet (sallal laahu alaihi wasallam) had taught this Nafil prayer to his Uncle, Hazrat Abbas (RA) and told him; He who performs this prayer will have his past and future sins forgiven.
The Prophet (sallal laahu alaihi wasallam) has recommended to read this prayer daily on each Friday or once a month or once a year, in case of this not being possible, to read it even once in one’s life. This Nafil prayer provides limitless benefits both in the material and spiritual life.
‘Ikrimah reports from Ibn ‘Abbas that the Messenger of Allah said to ‘Abbas ibn ‘Abdal-Mutalib: “O ‘Abbas, O Uncle, shall I not give you, shall I not present to you, shall I not donate to you, shall I not tell you ten things which, if you do, Allah will forgive your first and last sins, past and present sins, intentional and unintentional sins, private and public sins? The ten actions are: pray four rak’at, reciting in every rak’ah al-Fatihah and a surah. And when you finish the Qur’anic recitation of the first rak’ah, say, while standing, ‘Subhanallah, al-hamdulillah, wa la ilaha illallah, wa Allahu Akbar‘ ['Glory be to Allah. All praise is due to Allah. There is no God except Allah. Allah is the greatest.'] fifteen times. Then make ruku’, and while you are in ruku’, say the same ten times; then stand, and say the same ten times. Then go down and make sajdah, and while you’re in sajdah, say the same ten times. Then sit after the sajdah, and say the same ten times. Then make sajdah, and say the same ten times. Then sit after the second sajdah, and say the same another ten times. That is seventy-five [repetitions of the phrases] in each rak’ah. Do that in each of the four rak’at. If you can pray it once a day, do so. If you cannot, then once every Friday. If you cannot do that, then once a year. And if you cannot do that then once in your life.“
This hadith is related by Abu Dawud, Ibn Majah, Ibn Khuzaimah in his sahih, and at-Tabarani. About this hadith al-Mundhiri says: “This hadith has been related through many chains and from a number of companions. The best of them is this one from ‘Ikrimah. A group of scholars have graded it to be sahih, including al-Hafez Abu Bakr al-’Ajari, (al-Mundhiri’s teachers), Abu Muhammad ‘Abdurrahim al-Misri, and Abu al-Hassan al-Maqdisi.”
Ibn al Mubarak says: “The tasbih prayer is a greatly desired act and it is desirable that one should punctually observe it and never neglect it.
How to perform this Nafil:
After having pronounced one’s intention (Niyat), say Allaho-Akbar, read "Subhanaka-Alla humma" completely (Sana), read now 15 times "Subhaanallahi wal hamdu Lillaahi wala illaha Illallah Wallah-o-Akbar." Then read Aoozu billah and Bismillah (completely) and Surah Fateha. Then recite 10 times the Tasbih mentioned above and go to Ruku. Here also recite 10 times the Tasbih before raising yourself to read another 10 times the same Tasbih, this time in a standing position. Then prostrate (Sajdah) and read 10 times the Tasbih, sit now and read again 10 times this Tasbih (Jalsa) and prostrate again, Tasbish 10 times in the 2nd Raka-at begin by reading 15 times this Tasbih before reading "Bismillah" and Surah Fateha. After that read 10 times the Tasbih and then proceed as in the first Raka-at. To end the second Raka-at, read as usual "Attahiyat", "Durood" and "Duas".Then read 2 other Raka-ats. As in each Raka-at the Tasbih is recited 75 times, it means that in all 4 Raka-at the Tasbih is read 300 times. In the other 2 Raka-at, after "Subhana Rabbiyal-azeem",read the Tasbih 75 times and in the Sajdah (prostrations after Subhaan Rabbiyal-ala) read again 75 times the Tasbih.
Note: No fixed time has been prescribed for this prayer, a fact, which means that besides any time prohibited this prayer, can be read at any time.