My theory is that both Christianity and Islam exists because of the fact that deep prolonged mediation causes hallucinations and psychotic experiences. Why? Because God talked to both Jesus and Muhammed while they where meditating in the desert.
Also, in the gospel the story of the temptation in the wilderness comes after, not before, Jesus' recognition of his divine origin and mission. He was already baptized and pronounced to be God's son before ever going there. What's more this recognition has already come to him in childhood. And even if the order of events had been correct, then the nature of the events does not match, because when he was in the wilderness, Jesus was basically put to the test by the devil, who was trying to distract him from his divine commission, rather than being commissioned by God.