"Rabbana", or "Shajarian's Rabbana", is one of the revered works of Mohammad-Reza Shajarian, consisting of four supplications taken from the Qur'an. It is performed in the Segāh modal system, and each supplication begins with the phrase "Rabbana" (Our Lord). 
The piece was recorded in July 1979, and for 30 years it was one of the main broadcasts of Islamic Republic of Iran Broadcasting during the Islamic month of Ramadan. In May 2017, the piece was inscribed as a piece of Iran's intangible cultural heritage, with the registration number 1396.
According to Shajarian, because people had long been accustomed to hearing Seyyed Javad Zabihi’s rendition of the supplication "Rabbana" at iftar time, he composed a new version by adding two more Qur’anic verses and recorded it at a Radio Iran studio. His main motivation was to teach the piece to students who were to recite supplications on national television before iftar.
Mohammad-Reza Shajarian performed this supplication as a training version for his students to practice, unaware of its potential to rise to popularity.
Composition.
In 1979, transformations were underway in the music department of the Islamic Republic of Iran Broadcasting (IRIB), and the management was considering halting music production. During this time, Shajarian advocated for retaining talented staff in the music department. 
The leader of IRIB asked Shajarian to create a new piece suitable for broadcast before iftar in light of the political and religious shifts in Iran. Shajarian initially declined, saying he had been away from such content for years, but the director insisted: "Only you can do this—we have no one else." At that time, Shajarian had transferred from the Ministry of Agriculture to IRIB and was formally a National Iranian Radio and Television employee. He agreed and in the summer of 1979, started a training course for students who were to recite Dua al-Sahar and supplications. Soon after, he began recording the pieces.
Form.
Shajarian performed the piece in the Segah "dastgah" (musical modal system of Persian classical music). Throughout the piece, the melody modulates into other "dastgāhs" and "āvāzes" of the Persian radif tradition, including Āvāz-e Afshāri, but ultimately returns to Segāh. 
Rabbana was released as part of Shajarian’s album “Be Yād-e Pedar” (In Memory of Father).
This rendition is nearly devoid of vocal ornaments known as tahrir (a traditional trill-like technique) and, aside from a few pitches, is primarily performed using glissando and vibrato techniques. It begins with tones around B♭ and ascends to C, staying largely within this range (on a G-clef staff), and reaches its peak note at E♭.