The Hymn of the Pearl (also Hymn of the Soul, Hymn of the Robe of Glory or Hymn of Judas Thomas the Apostle) is a passage of the apocryphal Acts of Thomas. In that work, originally written in Syriac, the Apostle Thomas sings the hymn while praying for himself and fellow prisoners. Some scholars believe the hymn antedates the Acts, as it only appears in one Syriac manuscript and one Greek manuscript of the Acts of Thomas. The author of the Hymn is unknown, though there is a belief that it was composed by the Syriac gnostic Bardaisan due to some parallels between his life and that of the hymn.
The hymn tells the story of a boy, "the son of the king of kings", who is sent to Egypt to retrieve a pearl from a serpent. During the quest, he is seduced by Egyptians and forgets his origin and his family. However, a letter is sent from the king of kings to remind him of his past. When the boy receives the letter, he remembers his mission, retrieves the pearl and returns. That the boy is implicitly Thomas rather than Jesus is indicated by the eventual assertion that he is next in line to his elder brother, this unnamed brother not otherwise mentioned in the text.
The hymn is commonly interpreted as a Gnostic view of the human condition, that we are spirits lost in a world of matter and forgetful of our true origin. This state of affairs may be ameliorated by a revelatory message delivered by a messenger, a role is generally ascribed to Jesus. The letter thus takes on a symbolic representation of gnosis.
The hymn has been preserved and especially treasured in Manichaeism - a version of it appears as part of a north-African Manichaean Psalm book is written in Coptic, called the Psalms of Thomas. The Hymn of the Pearl has also been admired by Orthodox Christian thinkers and Mormons.