The Apostle Thomas (Hebrew or Aramaic for "twin") was also called "Didymus" (Greek for "twin"). He was absent when the Risen Lord appeared to the other apostles after the resurrection and refused to believe that Christ had indeed risen until he had seen him for himself, but when he had seen Him, he said to Him, "My Lord and My God." (John 20:19-29) ( Full details in the article by Dr. Matthew Vellanickal in the St. Thomas Christian Encyclopaedia of India [Ed. Prof. George Menachery, vol.2, 1973]; also Ibid. article by Msgr. Zaleski.)
Because of this episode, he has been known ever since as "Doubting Thomas." But we ought also to remember his earlier words, when Jesus announced His intention of going to the Jerusalem area, brushing aside the protests of His disciples that His life was in danger there, at which Thomas said to the others: "Let us also go, that we may die with him." (John 11:7,8,16) If Thomas was pessimistic, he was also sturdily loyal.

At the Last Supper, Jesus said: "I go to prepare a place for you.... And whither I go ye know, and the way ye know." Thomas replied: "Lord, we know not whither thou goest, and how can we know the way?" To this Jesus answered: "I am the way, the truth and the life." (John 14:1-6)

Thomas is mentioned again (John 21) as one of the seven disciples who were fishing on the Sea of Galilee (Sea of Tiberias) when the Risen Lord appeared to them. Aside from this he appears in the New Testament only as a name on lists of the Apostles. A couple of centuries later "The Acts of Judas Thomas" circulating in the Mediterranean world spoke of his preaching in India; and there is a Christian community in India (the Kerala State) viz. The Thomas Christians, that claims descent from Christians converted by the preaching of Thomas. ( For a detailed discussion of the "Acts of Judas Thomas" cf. The Indian Church History Classics, Ed. Prof. George Menachery, 1998, book reproduced "India and the Apostle Thomas" by A. E. Medlycott, fully available in the e-book on www.indianchristianity.com.

The tradition among Christians in India is that Thomas was speared to death near Madras, and accordingly he is often pictured holding a spear. Paintings of martyrs often show them holding or accompanied by the instruments with which they were put to death. He must have been using the spear as a supporting staff during his frequent journeys from the west coast to the east coast of India and back.

A recently discovered work called the Gospel of Thomas is a collection of sayings attributed to Jesus. Some scholarly support exist for the notion that it is the work of the Apostle Thomas, but many more scholars think that some of the sayings in it may be authentic sayings of Jesus. Here is a modern poem on the Apostle Thomas (For some lovely hymns on Thomas the Apostle nothing can compare with the works of the Deacon St. Ephraem, trans. into English by Medlycott vide. The Indian Church History Classics, vol.1 The Nazranies ed. G. Menachery, also available at http://www.indianchristianity.com/html/Books.html. Also see paper by Prof. Menachery on this topic at the 7th World Syriac Conference, SEERI:

Poem on Thomas

These things did Thomas hold for real:
The warmth of blood, the chill of steel,
the grain of wood, the heft of stone,
the last frail twitch of blood and bone.

His brittle certainties denied
That one could live when one had died,
until his fingers read like Braille
the markings of the spear and nail.

May we, O God, by grace believe
And, in believing, still receive
the Christ who held His raw palms out
and beckoned Thomas from his doubt.

(Thomas Troeger, 1984, Psalter/Hymnal of the Christian Reformed Church)

And here is a prayer to Thomas:
Almighty and everliving God, who didst strengthen thine apostle Thomas with sure and certain faith in thy Son's resurrection: Grant us so perfectly and without doubt to believe in Jesus Christ, our Lord and our God, that our faith may never be found wanting in thy sight; through him who liveth and reigneth with thee and the Holy Spirit, one God, now and for ever.