John II patriarch of Antioch, was a prominent and energetic church dignitary, a pious, intelligent and farsighted man. He entered the monastic order at the Monastery of Eusebuna where he mastered Greek and Syriac as well as theology. He became the disciple and secretary of Athanasius I and succeeded him to the Apostolic See in 631. He witnessed the Arab conquest of al-Jazira. He was a man who faced difficulties and hardships with patience and the course of events made him compliant.

At his behest, the Gospels were translated from Syriac into Arabic by a skillful Christian Orthodox Arab translators from the Bani 'Uqayl, Tanukh and Tay at the request of Umayr ibn Sa'ad ibn Abi Waqqas aI-Ansari the Amir of al-Jazira around 643, but this translation did not come down to us. With this Amir, he entered in to an elaborate dialogue on the establishment of the facts of Christianity, which was written down by Severus, one of his secretaries. It is titled "Letter of the Patriarch Mar John concerning His Conversation with the Amir of the Muslims." This letter was translated into French and published by Nau.

john also composed supplicatory prayers known as the Sedra or Husoye, which he incorporated into church rituals. They usually begin with praise and glorification. Of these Sedre we found a large collection in the oldest copy at the British Museum, most of which undoubtedly came from the pen of this Father who was nicknamed John of the Sedre." They are written in a smooth and splendid style. Nine of these Sedre bear his name, the first of which is for Lent, the second for the Resurrection, the third and the fourth for the repentance of sinners, the fifth for the dispelling of ordeals, the sixth for vespers, nocturn, morning and the seventh hour of prayer, the eighth for the dead and the ninth for the Friday morning of the fifth week of the fasting.323 We have also found three husoye of his for the celebration of the Eucharist, the first of which begins thus: "Praise be to the pure sacrifice who became the priest of his person;" the second begins thus: "Praise be to the heavenly Lord of hosts;" and the third begins: "0 Lord who art truly a good master." He has also drawn a liturgy which begins: "0 Lord, who art delighted by love and enjoyest safety;" a homily on the consecration of the Chrism, beginning thus: "Beloved brethren let us talk philosophically a little bit in behalf of this present sacred feast" and a letter to Marutha, Catholicos of Takrit, which he wrote at the beginning of his patriarchate. He also wrote a magnificent doctrinal treatise in thirty-nine pages addressed to the Chorepiscopus Theodorns, which he opened with a general proclamation to the children of the Holy Church, and declared in detail the creed of Faith in support of the true Apostolic belief, citing as evidence the Fathers, one of whom is John of Jerusalem. Furthermore, he condemned in this treatise the heresy of the Phantasiasts, and concluded it with the history of the leaders of this heresy and the account of their false ordinations. He died on the fourteenth of December, which is also the day of his commemoration.

(History of Syriac Literature and Sciences, Patriarch Ignatius Ephrem I Barsoum, Presseggiata Press, p 106)