Du'a Nudba is one of the major Shiite prayers about Muhammad al-Mahdi and his occultation. Nudba means to cry and Shiites read the prayer to ask for help during the occultation. The supplication is recited during Eid al-Fitr, Eid al-Adha, Eid al-Ghadeer, and every Friday morning.[1] Mazar al-Kabir, Mazar al-Ghadim, and Mesbaho al-Zaer were narrated the supplication. These books were written with authentic narrators such as Sayyed Ibn Tawus. Muhammad Baqir Majlisi wrote this prayer in Zaad-ul-Maad from Imam Ja'far al-Sadiq. Also, Albazofari, a person who lived in minor occultation, narrated from The Four Deputies of Imam Mahdi that Imam Mahdi said to read the prayer

The Imam then laments about the tragedies which befell the Family of the Prophet and the absence of the 12th Imam, who would fill the world with justice after countless eras of injustice.

Dua Nudba has been deemed authentic by scholars such as Sheikh Abbas Qummi, Allamah Majlisi, Sayed Raziuddin bin Tawoos and many more. This Dua is highly recommended to be recited on Friday and the days of Eid.
Friday is the day associated with the Zuhoor (return) of the 12th Imam