Mark creates several ironies which strongly suggest that he never intended for his readers to believe that his stories about Jesus were literally true. Four of these ironies are described below.
Taking Care of the Son of God
Mark creates a story in which Mary thinks that Jesus is out of his mind, and must be taken charge of (Mark 3:14-21, 31). Next to God himself, the last person one would expect to reject Jesus' divinity would be his mother. Who knows a man better than his own mother? Mark is able to make this believable because his gospel story has no birth narrative, as does Luke's, in which Mary is told by the angel that she would give birth to the son of God (Luke 1:26-35). If Mark's Mary had known that her Jesus was the son of God, she never would have thought he was out of his mind and needed taken care of; how could the all-powerful son of God be crazy and need taken care of?
This story not only illustrates Mark's use of irony--events occurring which are contrary to expectations, but also shows what seems to be his ignorance of the circumstances of Jesus conception and birth, if such had even occurred. Not only does the story seem to be fiction, but it also points to an apparent contradiction between Mark and Luke: Luke's Mary knows Jesus is the son of God, but Mark's Mary does not.
The Carpenter
Isaiah speaks of the "carpenter" who fashions false gods, and who cannot recognize the true god because his eyes are covered and he lacks understanding:
[C]raftsmen are nothing but men...The carpenter...makes a god...and says, "Save me; you are my god." They know nothing; they understand nothing; their eyes are plastered over so they cannot see... (Isaiah 44:9-20)
Mark puts this Isaiah passage to good use by constructing a triple irony in which the very people one would expect would be the first to recognize Jesus' divinity--the ones among whom he grew up--are among the first to scorn him; this is the first part of the irony triad. The second and third are found where Mark put the word "carpenter" on the ridiculing lips of the townspeople. How ironic that the one who is accused of being one who makes false gods is in essence God himself. And finally, how ironic it is that the one who scolded those who were unable to see and understand God (Mark 8:17-21), would be accused of being like a false-god-making carpenter who is unable to see and understand (Mark 6:1-4). Any notion that these perfect ironies actually existed outside the imagination of Mark is just too-farfetched to be taken seriously.
It's also telling that another gospel writer, Matthew, apparently didn't understand Mark's use of Isaiah here, and evidently didn't care much for the idea that Mark said the son of God was an ordinary carpenter, so Matthew changed Jesus from a carpenter to the son of a carpenter (Matthew 13:55).
The Son of the Father
Following Jesus' arrest, Mark creates a contest between the murderous "Barabbas," whose name means "son of the father," and Jesus, who, unknown to the crowd, was the real son of the father. Good doesn't always triumph over evil, but surely one would expect that the greatest of good, God, would triumph over a petty criminal. Not so in this case; Mark has the crowd choose the evil son of the father, instead of the good one. (Mark 15:1-18) The irony in this story is too delicious to be true, so it probably isn't.
Crowning the King
Mark's readers know (Mark 1:11) that Jesus is the all-loving son of God and that the crowd following the arrest does not know this, so they are well-prepared to appreciate the irony of the one who deserved to be crowned by men who loved him, but wasn't, instead being crowned by those who hated him. (Mark 15:17-18)
In summary, all four of these stories present unmistakable signs of being wholly or in part contrived to create irony. If one part of a gospel story is fictional, might not all of it be, and if one gospel story is completely fictional, why not all of the gospel stories? Perhaps the ultimate irony is that Mark's stories, which he probably intended never to be taken literally, are so taken even today by millions of fundamentalists.
Joseph F. Alward
"Skeptical Views of Christianity and the Bible"