Is the two-rak'ah prayer, followed by the supplication "O Allah, I ask You by Your Prophet, the Prophet of Mercy, O Prophet of Mercy, I have brought you to Allah so that He may fulfill my need," mentioned in the books of Sharia?

The aforementioned prayer and the supplication (du'a) thereafter have a basis in the Sunnah, as narrated by Tirmidhi, Ibn Majah, and others, from Uthman ibn Hunayf regarding the story of the blind man. The supplication mentioned in the Hadith is: "O Allah, I ask You and turn to You by Muhammad, the Prophet of Mercy. O Muhammad, I have turned to my Lord through you for this need of mine, so that it may be fulfilled. O Allah, so accept his intercession for me."

Shaykh al-Islam Ibn Taymiyyah is of the view that this supplication was specific to this blind man and to the time of the Prophet, peace be upon him, because the Hadith states that the blind man asked the Prophet, peace be upon him, to supplicate for him, and that he taught him to supplicate and say: "O Allah, accept his intercession for me." This is consistent with the Prophet's intercession and his supplication during his lifetime.

Therefore, supplicating with this supplication after his death, peace be upon him, is not legislated. As for the prayer of need (Salat al-Hajah), it is legislated.