The readings for today's feast at Matins in the traditional Benedictine Office are as follows:
Nocturn I: First Letter of St John 1:1-10; 2:1-5a
Nocturn II: From St Jerome on Ecclesiastical Writers; Commentary on Galatians
Nocturn III: Homily of St Augustine
All can be found on the Divinum Officium website. Here are the Second Nocturn readings, arranged as for the Benedictine Office:
(Reading 5): The Apostle John whom Jesus loved was a son of Zebedee, and brother of the Apostle James, who was beheaded by Herod soon after our Lord suffered. He was the last of the Evangelists to write his Gospel, which he published at the request of the Bishops of Asia, against Cerinthus and other heretics, and particularly against the then spreading doctrine of the Ebionites, who asserted that Christ had had no existence before Mary. It was therefore needful for the Evangelist to declare His Eternal and Divine Generation.
(Reading 6):In the fourteenth year after Nero, Domitian stirred up the second persecution, and John was exiled to the island of Patmos, where he wrote his Apocalypse, which hath been explained by Justin the Martyr and Irenaeus.
(Reading 7): When Domitian was killed, the Senate annulled all his acts, on account of his savage cruelty, and the Apostle returned to Ephesus, during the reign of Nerva. He remained at Ephesus until the time of Trajan, and founded and governed all the Churches of Asia. There, in an extreme old age, he died, in the sixty-eighth year after the Lord's passion, and was buried near the city.
(Reading 8):The Blessed Evangelist John lived at Ephesus down to an extreme old age, and, at length, when he was with difficulty carried to the Church, and was not able to exhort the congregation at length, he was used simply to say at each meeting, My little children, love one another. At last the disciples and brethren were weary with hearing these words continually, and asked him, Master, wherefore ever sayest thou this only? Whereto he replied to them, worthy of John, It is the commandment of the Lord, and if this only be done, it is enough.