What is the ruling on Salat al-Tasabih, and is there any authentic hadith concerning it?

Scholars have differed regarding the ruling on Salatul Tasabih (the Prayer of Glorifications). The majority of scholars hold it to be recommended, while the Hanbalis consider it not to be a Sunnah, though permissible to perform, on the grounds that a weak hadith may be acted upon concerning the virtues of deeds. Some, however, explicitly state its recommendability.

As for the hadith concerning it, it was narrated by Abu Dawud, Al-Tirmidhi, and Ibn Majah from Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace be upon him) said to Al-Abbas: "O my uncle, shall I not give you? Shall I not grant you? Shall I not bestow upon you? Shall I not do for you ten things, which if you do them, Allah will forgive your sins, the first and the last of them, the old and the new, the unintentional and the intentional, the small and the large, the secret and the open? Ten qualities: you pray four rak'ahs. In each rak'ah, you recite Surah Al-Fatiha and a surah. When you finish the recitation, you say: 'Subhanallah, Walhamdulillah, Wa La ilaha illallah, Wallahu Akbar' (Glory be to Allah, and praise be to Allah, and there is no god but Allah, and Allah is the Greatest) fifteen times. Then you bow, and while bowing, you say it ten times. Then you raise your head from bowing, and you say it ten times. Then you prostrate, and while prostrating, you say it ten times. Then you raise your head from prostration, and you say it ten times. Then you prostrate again, and you say it ten times. Then you raise your head, and you say it ten times. That is seventy-five times in each rak'ah. You do this in the four rak'ahs. If you are able to pray it once every day, then do so. If you cannot, then once every Friday. If you cannot, then once every month. If you cannot, then once every year. If you cannot, then once in your lifetime."

Hadith preservers have differed in their judgment of this hadith. Some have authenticated it, and they are the majority of verifying scholars, while others have weakened it. However, the truth is that the hadith does not fall below the grade of 'hasan' (good) due to the multitude of its chains of narration, which strengthen it.