The majority of the scholars say that it is preferred to make prostrations of thankfulness (shukr) when one receives a bounty (good news) or is rescued from some trial. Abu Bakr reports that, when the Prophet received something which pleased him or some glad tidings, he would make the sajdah in thanks to Allah. Abu Dawud, Ibn Majah, and at-Tirmizhi
'Abdurrahman ibn 'Auf relates that the Messenger of Allah went out once and he followed him until he entered a grove of palm trees and prostrated. His prostration was so long that 'Abdurrahman feared that Allah had taken his soul. 'Abdurrahman came to look at him and he raised his head and said: "What is wrong, Abdurrahman'?" Abdurrahman mentioned what had happened, and he said: "Gabriel (as) came to me and said: 'Shall I not give you glad tidings'? Allah says to you: ‘Whoever prays upon you, I pray upon him. Whoever salutes you, I salute him.' Therefore, I prostrated to Allah in thanks."This is related by Ahmad and by AlHakim who says: "It is sahih according to the criterion of al-Bukhari and Muslim. And I do not know anything moreauthentic than that."
Al-Bukhari records that Ka'b ibn Malik made a sajdah when he received the news that Allah had accepted his repentance. Ahmad records that 'Ali performed the sajdah when he heard the news that Zhul-Thudayyah of the Khawarij was killed. Also, as mentioned before, Sa'id ibn Mansur recorded that Abu Bakr made sajdah in thankfulness when Musailimah was killed.
The prostration of thankfulness is bound by the same requirements as the prostration in prayer, while some disagree as it is not a prayer. The author of Fath al-'Alam remarks: "This latter opinion is closer to being correct." Ash-Shaukani said: "There is nothing in the hadith to prove that ablution and purity of the clothes and place are required for sajdat-ush shukr. And that is the opinion of Imam Yahya and Abu Talib. And these hadith are silent about any takbir being made with the prostration. In alBahr it is stated that there is a takbir. Imam Yahya says: 'One is not to make the prostration of thankfulness during a prayer as it is not part of the prayer.'"
Fiqh-us-Sunnah, Volume 2: The Prostration of Thankfulness (Sajdatush-Shukr)
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