Rabbulas (or Rabbula) was a bishop of Edessa (411 - August, 435), noteworthy for his opposition to the views of Theodore of Mopsuestia, as well as those of Nestorius. However, his successor Ibas, who was in charge of the school of Edessa, reversed the official stance of that bishopric.

He was a native of Kenneschrin , a town some few miles south of Aleppo and the seat of a bishopric. His father was a pagan priest, and though his mother was a devoted Christian he remained a pagan until some time after his marriage. During a journey to his country estates he was converted to Christianity partly through coming in contact with a case of miraculous healing and partly through the teaching and influence of Eusebius, bishop of Kenneschrin, and Acacius, bishop of Aleppo.

With all the energy of his fiery nature he threw himself into the practice of Christian asceticism, sold all his possessions, and separated from his wife and kinspeople. He resided for some time in a monastery, and then passed to a life of greater hardship as a solitary hermit. On the death of Diogenes, bishop of Edessa, in the year 411-412, Rabbulas was chosen his successor, and at once accepted the position offered him, without any of the customary show of reluctance.

As a bishop he was marked by extraordinary energy, by the continued asceticism of his personal life, by his magnificent provision for all the poor and suffering in his diocese, by his care for discipline among the clergy and monks who were under his authority, and latterly by the fierce determination with which he combated all heresies and especially the growing school of the followers of Nestorius. On one occasion he visited Constantinople and there preached before Theodosius II (who was then favorable to Nestorius) and a great congregation a sermon in denunciation of Nestorian doctrine, of which a portion survives in the Syriac version.

He became the friend of Cyril of Alexandria, with whom he corresponded, and whose treatise De recta fide he translated into Syriac. After a busy episcopal life of twenty-four years he died in August 435, and was succeeded by Ibas.

The literary remains of Rabbulas are small in bulk, and are mostly to be found in Overbeck. Perhaps his main importance to the historian of Syriac literature lies in the zeal with which he strove to replace the Diatessaron or Gospel Harmony of Tatian by the edition of the separate Gospels, ordering that a copy of the latter should be placed in every church and should Overbeck, op. cit. pp. 239-244.

The version survives in a British Museum manuscript; see Wright's Syr. Lit. p. 9. According to his biographer (Overbeck, p. 172) he himself produced a version (or revision) of the New Testament in Syriac, known as the Peshitta. Rabbulas' involvement may have been, as Wright suggests (Syr. Lit. p. II), a first step in the direction of the Philoxenian version. FC Burkitt went further and advanced the hypothesis that Rabbula, at least as regards the Gospels, actively helped in the translation of the current Peshitta text, using the Greek text as read in Antioch about 400. However, since then Arthur Vöörbus (Investigations into the Text of the New Testament used by Rabbula of Edessa [Pinneburg, 1947]) has furnished evidence that the Peshitta was older than Rabbulas' time.