The phrase “Believe and do not investigate” has over the centuries become a sharp weapon deliberately wielded by critics of Christianity to wound and discredit the supporters of this religion, accusing them of narrow-mindedness and bigotry.

Attributed by some to the Bible and by others to the voice of the Church, the phrase “Believe and do not investigate” has origins that are little known to those who use it. Some attribute it to medieval theology without providing any concrete evidence. Others connect it to the biblical episode where Jesus Christ reproaches the apostle Thomas for feeling the need to put his finger on Jesus’s wound in order to believe that He had risen. However, there is no biblical verse where this expression appears. And this is for one simple reason: it doesn’t appear anywhere in the Bible.

In reality, things are quite the opposite. Christianity did not give birth to this expression with the supposed aim of keeping its own members in ignorance, but rather it was birthed by the opponents of Christianity, driven by the desire to cast a negative light on a religion that was unsettlingly on the rise. Specifically, the phrase belongs to the Greek philosopher Celsus (2nd century AD), an opponent of early Christianity.

Celsus is known for his work The True Word, preserved through the Christian theologian Origen (†254). It is a work in which Celsus sought to ridicule Christianity. He portrays Jesus Christ as being born out of an adulterous relationship between a young, poor Jewish girl and a Roman soldier named Panthera. In the philosopher’s opinion, Christ was nothing more than a sorcerer who practised begging and claimed to be God.

The Bible’s injunction is rather: “Believe, but investigate!”

Knowing from the Gospels the story of the miraculous birth of Jesus, Celsus did nothing but deny this detail, offering an explanation that seemed more plausible to him and suspiciously similar to some details from hostile Jewish sources about Jesus. Origen recalls in the chapter “Ignorance, Irrationality, and Superstition” from the book Against Celsus, that the Greek philosopher asserted about some Christians that “they do not even want to accept arguments for what they believe, but use expressions like ‘Believe and do not investigate.’”

So, this is the context in which the famous phrase appeared. Despite the myth, it was not the Bible or the Church that promoted this expression, but rather an opponent of Christianity.

It should be noted that, in reality, the Bible encourages exactly the opposite spirit of this phrase. One of the prophets of the Old Testament says, “Look in the scroll of the Lord and read” (Isaiah 34:16), and in the New Testament, the apostle Paul speaks approvingly of the believers from the town of Berea, who “examined the Scriptures every day to see if what Paul said was true” (Acts 17:11). The Bible’s injunction is rather: “Believe, but investigate!”