The Gospel of Thomas, containing the sayings of the “living” Jesus and found at Nag Hammadi (Codex II, 2, which is the second document in the second book), is a complete and well-preserved papyrus manuscript written in Egyptian Coptic script that dates to about A.D. 340. There are earlier Greek fragments that date to about A.D. 200. The Coptic version, scholars believe, was translated from the original Greek. Three other fragments of this gospel were previously discovered in 1898 at Oxyrhynchus, Egypt.

The sayings may be interpreted with Gnostic meaning and context, but because the term “Gnostic” is being hotly debated, some scholars hesitate to call the Gospel of Thomas a Gnostic text. However, since it was found with other Gnostic texts and was also written in the Coptic Egyptian script, it may be judged Gnostic because of that association. Some say that since the Greek fragments of the Gospel of Thomas are much older than the copy found at Nag Hammadi, the Gnostic labeling of the gospel should be removed. Another reason for removing the Gnostic classification is that the Gospel of Thomas does not contain the complex mythology of Gnosticism that modern scholars now associate with Gnostic texts. Nevertheless, it is included in James Robinson's The Nag Hammadi Library: The Definitive Translation of the Gnostic Scriptures Complete in One Volume. Scholar Helmut Koester raised an issue of concern about the Gospel of Thomas in the introduction to the gospel in The Nag Hammadi Library, namely, that the Greek fragments and the Coptic version seemingly have not preserved the Gospel of Thomas in its oldest form. In other words, the text may have changed with subsequent copying.

Many of the wisdom sayings in the Gospel of Thomas are similar to those contained in the New Testament gospels, although some seem to differ, even conflict. There is no narrative structure to this gospel. Spiritual seekers most likely interpreted the sayings or used the sayings as points of contemplation or departure into meditation in order that gnosis — true knowledge — might come. The Gnostics believed that instead of becoming a Christian, through gnosis you became a Christ. Indeed, the sayings may be yeast for the gnosis. Some of the wisdom sayings contained in the gospel point to the Gnostic belief in dualism, the heavenly realm of light and goodness with the dark realm of material existence that is imperfect and evil. Some of the wisdom sayings in the Gospel of Thomas do not depend on the New Testament gospels and may have been in existence before the canonical versions of them were written. Marvin Meyer, in his book The Gospel of Thomas: The Hidden Sayings of Jesus, suggests that this might be true for the saying commonly known as the Parable of the Sower, which also appears in Matthew, Mark, and Luke. In the Parable of the Sower, Jesus talks about a farmer who sows his seed. In one instance, some seeds fall by the wayside; in the second instance, some fall upon a rock. Seeds also fell among thorns, and some landed on good ground and bore fruit. In the New Testament Gospels, an explanation or interpretation follows the parable itself, applying the meaning to church experience. Here's the interpretation found in the New Testament Gospel of Luke that follows Luke's Parable of the Sower (Luke 8:5–8). Jesus speaks the parable and then gives the interpretation.

The Gospel of Thomas does not contain interpretations. The presence of interpretations after the sayings means that interpretations were added later in the canonical versions of the sayings, asserted Meyer. He also pointed out that the Gospel of Thomas and the other sayings gospel, Q, create a paradigm for glimpsing and studying the historical Jesus.