Answer
Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- Offering Supererogatory Prayers is one of the effective means that bring man close to Allah.
2- There is no authentic evidence to recommend the practice of Salat al-Tasbih.
In responding to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
Salat al-tasbih: Controversial Form of Prayer
“Salat al-tasbih is a highly controversial form of prayer. While considered by some to be a Nafl entailing great blessings, many scholars consider it as weak, dubious, and, therefore, not worthy of consideration.
Evidence
Those who uphold and advocate the benefits of this prayer have based their view on the following Hadith attributed to Prophet Muhammad (peace be on him):
“Prophet Muhammad said to his uncle Al-Abbas: “O Abbas, my dear uncle, shall I give you, shall I gift you, shall I bestow on you ten special gifts. If you do what I am going to tell you shortly, you will gain the following ten benefits: Allah will forgive all your sins: both the first and the last, the old and the new, the conscious ones as well as the unconscious, the small and the big, the private and the public – ten things altogether. You should perform four Rakahs (of prayer), and in the first Rak`ah you should read Fatihah and a Surah. After having done so, while still standing, read the following:
“Subhaana Allah, waal-hamdu lillaah, walaa ilaaha illa Allah, wa Allahu akbar” 15 times, then you go to Ruku and recite the above again 10 times, then lift your head up from Ruku and say, while standing, the same words 10 times, then, go to Sujud and say the same 10 times, then, rise from Sujud and while sitting say it again 10 times.
Afterwards, you should go back to Sujud again, and say the same words 10 times, then, raise your head from Sujud and, again, say the same 10 times: It adds up to a total of 75 Tashbihs in each Rak`ah. You must do the same in each of the four Rak`ahs. If you can do it once in every Jumu`ah do so; if you cannot, then do it once a month, if you cannot, do it once a year, if you cannot, do it once in your life-time at least.” (Abu Dawud)
The above report is not to be found in the Sahih of Al-Bukhari or the Sahih Muslim or the Muwatta of Imam Malik. It had been unknown to the great Imams such as Malik, Abu Hanifah and, presumably, to Imam Shafi`i, and it was considered strange and unworthy of consideration by Imam Ahmad.
The above Hadith is listed among the fabricated Hadiths by Ibn Al-Jawzi.
According to Imam Ibn Hajar: “All of the chains of this Hadith are weak” Also, “It is contrary to the prescribed format of Prayer.”
Ibn Hajar further added, “It had been declared as weak by both Ibn Taymiyyah and Al-Mizzi.”
In the words of Ibn Al-Arabi, “There is not a single authentic or sound Hadith on it.”
Imam Nawawi has also joined the ranks of scholars questioning the nature of the report as well as the strange format of Salat al-Tasbih, and hence, considering it as unworthy of consideration.
The Ruling
In light of the above, it is only reasonable to state there is no authentic evidence to recommend the practice of Salat al-Tasbih.
Besides, we have sufficiency in what has been authentically transmitted from the Prophet and accepted by the Ummah at large – such as Salat al-Al-Hajah, Salat al-Istikharah, Salat al-Tawbah, etc. Thus, we do not need to resort to such a highly contentious form of prayer.
Moreover, we believe that Prophet Muhammad has conveyed to us plainly and clearly everything we ought to do in this religion of Islam.
Almighty Allah knows best.