Answer
Mythicism is the belief that Jesus Christ never existed as a historical figure but was derived from a group of mythical gods and demigods from Greek and Roman times. Mythicism claims that, since certain supernatural powers or feats were described prior to the rise of Christianity, then Christians could have simply incorporated them into their new religion.
For example, a mythicist might believe that followers of Christ “borrowed” the powers ascribed to Asclepius, the Greek god of medicine (Jesus is called the Great Physician), fathered by the god Apollo and his mother, a mortal woman (Jesus is the Son of the Father and was born of a virgin). The symbol of Asclepius was a serpent wound around a staff, and Jesus compared Himself to a serpent that was lifted up in the desert by Moses as a foreshadowing of His being raised up on the cross (Numbers 21:9; John 3:14–15). Mythicists use these examples and others to defend their beliefs.
Mythicism denies that Jesus has come in the flesh and is from God. But the apostle John warns against the empty philosophies that deny the One who came to save mankind. Such denials are of the devil. “Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world. By this you know the Spirit of God: Every spirit that confesses that Jesus Christ has come in the flesh is of God, and every spirit that does not confess that Jesus Christ has come in the flesh is not of God” (1 John 4:1–3a).
The truth is that Jesus really did exist. The truth is that the Gospels are not copies of ancient mythologies. The claims of mythicism are totally false, and, like all lies, they are designed to catch the unsuspecting and shipwreck the faith of immature believers. The only sure way to recognize the lies is to be intimately familiar with the Truth. We do this by seeking truth in everything and comparing everything we hear with the Word of God, just as the Bereans did. “These were more fair-minded than those in Thessalonica, in that they received the word with all readiness, and searched the Scriptures daily to find out whether these things were so. Therefore many of them believed, and also not a few of the Greeks, prominent women as well as men” (Acts 17:11–12).