Syriac writer described for his learning and holiness as “the flute of the Holy Spirit and the harp of the believing church.”

Like his father, Jacob was ordained a priest, and by 503 he was episcopal visitor of Haura in Serugh. In 519 he was made bishop of Baṭnan in Serugh. By his contemporaries and by some moderns Jacob has been regarded as orthodox, but four of his letters prove his acceptance of the theology of Cyril of Alexandria on the divine subject in Christ. His prose writings include discourses, six festal homilies, and many letters. He is the reputed author of a liturgy and order of baptism. He also wrote 760 homiletic poems, only about half of which are extant. The poems are mostly in dodecasyllabic metre, treating mainly of Old and New Testament incidents and persons.