Thaddaeus was one of the Seventy Apostles but not the Thaddaeus who was one of the Twelve Apostles. St. Thaddaeus first saw and heard John the Baptist and received baptism from him and after that he saw the Lord Jesus and followed Him. The Lord numbered him among the seventy lesser apostles whom He sent two by two before His face, “After these things, the Lord appointed other seventy also and sent them two and two before His face into every city and place where He Himself would come” (St. Luke 10:1). After His glorious Resurrection and Ascension, the Lord sent Thaddaeus to Edessa, Thaddaeus’ birthplace, according to the promise He gave to Prince Abgar at the time when He sent the towel with His face on it. By kissing the towel, Abgar was healed of leprosy but not completely. A little leprosy still remained on his face. When St. Thaddaeus appeared to Abgar, he received him with great joy. The apostle of Christ instructed him in the true faith and after that baptized him. When the baptized Abgar came out of the water, the remaining leprosy fell from him and he was completely healed. Glorifying God, Prince Abgar also wanted that his people should know the true God and to glorify Him. The prince assembled all the citizens of Edessa before the holy Apostle Thaddaeus to hear teaching about Christ. Hearing the words of the apostle and seeing their prince miraculously healed, the people rejected the idols, unclean living, embraced the Faith of Christ and were baptized. Thus, the city of Edessa was illumined by the Faith of Christ. Prince Abgar brought much gold and offered it to the apostle but Thaddaeus said to him: ” Since we left our own gold, how can we receive the gold of others?” St. Thaddaeus preached the Gospel throughout Syria and Phoenicia. He reposed in the Lord in the Phoenician city of Beirut. (The place of his death is indicated as Beirut in the Slavonic MENAION, but according to other sources he died in Edessa. According to an ancient Armenian tradition, St Thaddeus, after various tortures, was beheaded by the sword on December 21 in the Artaz region in the year 50)
Apolytikion in the Third Tone
O Holy Apostle Thaddeus, intercede to our merciful God, that He may grant our souls forgiveness of sins.
Kontakion in the Third Tone
The Apostle’s joyous feast is come with radiant splendour; let us keep it on this day with jubilation and gladness. For to them who ever honour him in sincere faith, it doth grant their sins’ forgiveness and true divine health; for he hath great boldness as a divine initiate of Christ’s omnipotent grace.
by Saint Nikolai Velimirovich
The Prologue from Ohrid