Thomas the Apostle (Classical Syriac: ܬܐܘܡܐ, romanized: Tʾōmā, lit. 'the Twin') also known as Didymus (Greek: Δίδυμος, romanized: Dídymos 'twin'), was one of the Twelve Apostles of Jesus according to the New Testament. Thomas is commonly known as "doubting Thomas" because he initially doubted the resurrection of Jesus when he was told of it (as is related in the Gospel of John); he later confessed his faith ("My Lord and my God") on seeing the places where the wounds appeared still fresh on the holy body of Jesus after the Crucifixion of Jesus.
According to early Christian tradition, it was at or near Muziris that Thomas the Apostle is believed to have first arrived in India. He started the Church of the East in the region around the Van Province, Edessa, and Hakkari regions of Upper Mesopotamia (modern-day southeastern Turkey), presumably sometime between mid-late 30s and 45, and spent many years evangelizing both Jews and non-christians in the area before heading further east in the late 40s. In 1258, some of the relics were brought to Ortona, in Abruzzo, Italy, where they have been held in the Church of Saint Thomas the Apostle. He is regarded as the patron saint of India among Saint Thomas Christians, and the Feast of Saint Thomas on July 3 is celebrated as Indian Christians' Day. The name Thomas remains quite popular among the Saint Thomas Christians of the Indian state of Kerala.
Many churches in the Middle East and southern Asia, besides India, also mention Apostle Thomas in their historical traditions as being the first evangelist to establish those churches, the Church of the East, as well as the early church of Sri Lanka.
Thomas first speaks in the Gospel of John. In John 11:16, when Lazarus has recently died, and the apostles do not wish to go back to Judea, Thomas says: "Let us also go, that we may die with him."
Thomas speaks again in John 14:5. There, Jesus had just explained that he was going away to prepare a heavenly home for his followers, and that one day they would join him there. Thomas reacted by saying, "Lord, we know not whither thou goest; and how can we know the way?"
John 20:24–29 tells how doubting Thomas was skeptical at first when he heard that Jesus had risen from the dead and appeared to the other apostles, saying, "Except I shall see on his hands the print of the nails, and put my finger into the print of the nails, and thrust my hand into his side, I will not believe." But when Jesus appeared later and invited Thomas to touch his wounds and behold him, Thomas showed his belief by saying, "My Lord and my God". Jesus then said, "Thomas, because thou hast seen me, thou hast believed: blessed are they that have not seen, and yet have believed."
The name Thomas (Greek: Θωμᾶς) given for the apostle in the New Testament is derived from the Aramaic תְּאוֹמָא Tʾōmā (Syriac ܬܐܘܿܡܵܐ/ܬ݁ܳܐܘܡܰܐ Tʾōmā/Tāʾwma), meaning "the twin" and cognate to Hebrew תְּאוֹם tʾóm. The equivalent term for twin in Greek, which is also used in the New Testament, is Δίδυμος Didymos.
The Nag Hammadi copy of the Gospel of Thomas begins: "These are the secret sayings that the living Jesus spoke and Didymus, Judas Thomas, recorded." Early Syrian traditions also relate the apostle's full name as Judas Thomas. Some have seen in the Acts of Thomas (written in east Syria in the early 3rd century, or perhaps as early as the first half of the 2nd century) an identification of Thomas with the apostle Judas, Son of James. However, the first sentence of the Acts follows the Gospels and the Acts of the Apostles in distinguishing the apostle Thomas and the apostle Judas son of James. Others, such as James Tabor, identify him as Jude, brother of Jesus mentioned by Mark. In the Book of Thomas the Contender, part of the Nag Hammadi library, he is alleged to be a twin to Jesus: "Now, since it has been said that you are my twin and true companion, examine yourself…"
A "doubting Thomas" is a skeptic who refuses to believe without direct personal experience—a reference to the Gospel of John's depiction of the Apostle Thomas, who, in John's account, refused to believe the resurrected Jesus had appeared to the ten other apostles until he could see and feel Jesus' crucifixion wounds.
When the feast of Saint Thomas was inserted in the Roman calendar in the 9th century, it was assigned to 21 December. The Martyrology of St. Jerome mentioned the apostle on 3 July, the date to which the Roman celebration was transferred in 1969, so that it would no longer interfere with the major ferial days of Advent. Traditionalist Roman Catholics (who follow the General Roman Calendar of 1960 or earlier), the Lutheran Church, and many Anglicans (including members of the Episcopal Church as well as members of the Church of England who worship according to the 1662 edition of the Book of Common Prayer), still celebrate his feast day on 21 December. However, most modern liturgical calendars (including the Common Worship calendar of the Church of England) prefer 3 July, Thomas is remembered in the Church of England with a Festival.
The Eastern Orthodox venerates Thomas on the following days:
June 20 – Commemoration of the Translation of the Relics of the Apostles Andrew, Thomas, and Luke; the Prophet Elisha; and the Martyr Lazarus.
June 30 – The Twelve Apostles.
October 6 – Primary feast day.
The First Sunday after Easter – The Sunday of Thomas, which commemorate when Thomas' doubts regarding the risen Christ were removed by Christ displaying the wounds in his hands and side.
Thomas is also associated with the "Arabian" (or "Arapet") icon of the Theotokos (Mother of God), which is commemorated on 6 September. He is also associated with the Cincture of the Theotokos, which is commemorated on August 31.
The Malankara Orthodox Church celebrates his feast on three days, 3 July (in memory of the relic translation to Edessa, modern Şanlıurfa), 18 December (the Day he was lanced), and 21 December (when he died).
The Passing of Mary, adjudged heretical by Pope Gelasius I in 494, was attributed to Joseph of Arimathea. The document states that Thomas was the only witness of the Assumption of Mary into heaven. The other apostles were miraculously transported to Jerusalem to witness her assumption. Thomas was left in India, but after her first burial, he was transported to her tomb, where he witnessed her bodily assumption into heaven, from which she dropped her girdle. In an inversion of the story of Thomas' doubts, the other apostles are skeptical of Thomas' story until they see the empty tomb and the girdle. Thomas' receipt of the girdle is commonly depicted in medieval and pre-Council of Trent Renaissance art.