Lebbaeus, who also is Thaddaeus, was from the city of Edessa - and it is the metropolis of Osroene, in the interior of the Armenosyrians - an Hebrew by race, accomplished and most learned in the divine writings. He came to Jerusalem to worship in the days of John the Baptist; and having heard his preaching and seen his angelic life, he was baptised, and his name was called Thaddaeus. And having seen the appearing of Christ, and his teaching, and his wonderful works, he followed him, and became his disciple; and he chose him as one of the twelve, the tenth apostle according to the Evangelists Matthew and Mark.

In those times there was a governor of the city of Edessa, Abgarus by name; and when the fame of Christ had spread, of the wonders which he did and of his teaching, Abgarus heard of it, and was astonished and desired to see Christ, but could not leave his city and government. And about the days of the Passion and the plots of the Jews, Abgarus, being seized by an incurable disease, sent a letter to Christ by Ananias the courier, to the following effect: "To Jesus called Christ, Abgarus the governor of the country of the Edessenes, an unworthy slave. The multitude of the wonders done by you has been heard of by me, that you healest the blind, the lame, and the paralytic, and cure all the demoniacs; and on this account I ask your goodness to come even to us, and escape from the plottings of the wicked Jews, which through envy they set in motion against you. My city is small, but large enough for both. Abgarus enjoined Ananias to take accurate account of Christ, of what appearance he was, and his stature, and his hair, and in a word everything."

And when Ananias had gone and given the letter, he was carefully looking at Christ, but was unable to fix him in his mind. But Christ knew him as knowing the heart [of all], and asked to wash himself; and a towel was given him; and when he had washed himself, he wiped his face with it. And his image having been imprinted on the linen, he gave it to Ananias, saying: "Give this, and take back this message to the one who sent you: Peace to you and to your city! For because of this I am come, to suffer for the world, and to rise again, and to raise up the forefathers. And after I have been taken up into the heavens I shall send you my disciple Thaddaeus, who shall enlighten you, and guide you into all the truth, both you and your city." And Ananias, having received it and fallen down and adored the likeness, Abgarus was cured of his disease before Thaddaeus came. But after the passion, and the resurrection, and the ascension, Thaddaeus went to Abgarus; and finding him in health, he gave him an account of the incarnation of Christ, and baptised him, with all his house. And having instructed great multitudes, both of Hebrews and Greeks, Syrians and Armenians, he baptised them in the name of the Father, and Son, and Holy Spirit, anointing them with the holy perfume; and he communicated to them the undefiled mysteries of the sacred body and blood of our Lord Jesus Christ, and delivered to them to keep and observe the Law of Moses, and to give close heed to the things that were said by the apostles in Jerusalem - for year by year they came together to the Passover; and again he imparted to them the Holy Spirit.

Now Thaddaeus along with Abgarus destroyed idol-temples and built churches; ordained as bishop one of his disciples, and presbyters, and deacons, and gave them the rule of the psalmody and the holy liturgy. And having left them, he went to the city of Amis, great metropolis of the Meso-Chaldeans and Syrians, that is, of Mesopotamia-Syria, beside the river Tigris. And he having gone into the synagogue of the Jews along with his disciples on the Sabbath-day, after the reading of the Law the high priest said to Thaddaeus and his disciples: "Men, where are you from; and why are you here?

Thaddaeus said: "No doubt you have heard of what has taken place in Jerusalem about Jesus Christ, and we are his disciples, and witnesses of the wonderful things which he did and taught, and how through hatred the chief priests delivered him to Pilate the procurator of Judaea. And Pilate, having examined him and found no case, wished to let him go; but they cried out, If you let him go, you are not Caesar's friend, because he proclaims himself king. And he being afraid, washed his hands in the sight of the multitude, and said, I am innocent of the blood of this man; see you to it. And the chief priests answered and said, his blood be on us and our children. And Pilate gave him up to them. And they took him, and spit on him, with the soldiers, and made a great mock of him, and crucified him, and laid him in the tomb, and secured it well, having also set guards on him. And on the third day before dawn he rose, leaving his burial-clothes in the tomb. And he was seen first by his mother and other women, and by Peter and John first of my fellow disciples, and thereafter to us the twelve, who ate and drank with him after his resurrection for many days. And he sent us in his name to proclaim repentance and remission of sins to all the nations, that those who were baptised, having had the kingdom of the heavens preached to them, would rise up incorruptible at the end of this age; and he gave us power to expel demons, and heal every disease and every malady, and raise the dead."

When the multitudes heard this, they brought together their sick and demoniacs. And Thaddaeus, going out along with his disciples, laid his hand on each one of them, and healed them all, by calling on the name of Christ. And the demoniacs were healed before Thaddaeus came near them, the spirits going out of them. For many days the people ran together from different places, and saw what was done by Thaddaeus. And hearing his teaching, many believed, and were baptised, confessing their sins.

Remaining with them for five years, he built a church; and having appointed as bishop one of his disciples, and presbyters, and deacons, and prayed for them, he went away, going round the cities of Syria, and teaching, and healing all the sick; whence he brought many cities and countries to Christ through his teaching. Teaching, therefore, and evangelizing along with the disciples, and healing the sick, he went to Berytus, a city of Phoenicia by the sea; and there, after having taught and enlightened many, he fell asleep on the twenty-first of the month of August. And the disciples came together, and buried him with great honour; and many sick were healed, and they gave glory to the Father, and the Son, and the Holy Spirit, for ever and ever. Amen.