In this article Anton Baumstark presents the Arabic text of the Testamentum Domini Nostri Jesu Christi found in a manuscript of various liturgical materials (Museo Borgiano K IV 21). Baumstark notes that the text is similar to the Syriac version of the Testamentum published by Ignatius Ephraem II Rahmani, but Baumstark also argues that the prayers and liturgical materials in this text represent a separate recension from that preserved in the Syriac sources. In the introduction to the text, Baumstark concludes that the text can concretely be dated between the seventh- and tenth-centuries, but ultimately he argues in favor of a late seventh-century dating. Thus, Baumstark argues that this form of the liturgy represents a stage in the development of Egyptian Christianity prior to many sources previously published, and thus provides a valuable resource for the practice of Christianity in Egypt. Baumstark also compares the text with contemporary liturgical sources and concludes that, while there is clearly a Syriac influence on portions of the text, the baptismal prayers represent a form distinct from the Syriac/Antiochene and Byzantine forms. Baumstark includes the Arabic text along with a Latin translation and brief critical notes where applicable.