Why was the Book of Thomas not incorporated into the Holy Bible?

The “Book of Thomas” in question here refers to a document called the Gospel of Thomas. This text is an apocryphal work, meaning that it is not accepted as canonical. The text is very old though, dating at least back to the 2nd century AD and perhaps even further back to the 1st century AD.

First, I should mention that the Gospel of Thomas was actually not written by St. Thomas the Apostle. The true author of the text is anonymous. The book is also not a “gospel” like the four Gospels in the Bible–by this I mean that it isn’t an account of Jesus’ life. Rather, it’s a collection of sayings of Jesus, like a book of proverbs.

Being an apocryphal work, the Gospel of Thomas is not included in the Bible. Its non-canonical status comes down to several reasons, but the most important one is that it contains heretical teachings. The book originates from a circle of early Christians who were influenced by a heresy known as Gnosticism. This heresy contained many strange and obscure teachings, including hatred of the body and the search for hidden knowledge.

The Church condemned Gnosticism fiercely in its early days, which is probably part of the reason the book was only discovered in the 1900s. It may not have even been widely known outside of the small and obscure group of Christians who compiled it.One interesting tidbit, however, is that some of the sayings in the Gospel of Thomas are the same as (or very similar to) the sayings of Jesus in the actual Gospels. That’s because the communities where all these books came from may have all been familiar with those sayings of Jesus. However, the Gospel of Thomas also makes edits here and there which make Jesus sound much more like a mouthpiece of Gnostic ideas. So while the book is interesting from an archaeological and historical perspective, the Church (from its beginning) has affirmed that the book is not inspired Scripture.