I follow Bruno Bauer's idea that the Temptation story is a mere expedient by "Mark" to explain why Jesus didn't return directly to home in Galilee after the baptism: had he done so, Jesus would be returned to the his original status of a pious Jew not still aware of being god (or possessed by god). "Mark" wanted that Jesus returned to Galilee as a god (more precisely: as the god predicted by John the Baptist), not as a mere human being.
But precisely in the writing of Mark, who usually does not leave any part of his account unmotivated, we should expect to be told the purpose for which Jesus was driven into the wilderness. The more violent the way in which the Spirit brought (ἐκβάλλει) Jesus into the wilderness, the more certain we can be that there must have been a special reason for this stay in solitude. Mark cannot mean to say that Jesus stayed in the wilderness for a long, indefinite time; for (C. 1, 9.) Jesus comes from Galilee to the baptism, and he returns to Galilee when the Baptist was arrested. Therefore, Mark had to say necessarily why and how long Jesus had kept himself away from his home
Corollary: the Temptation story is organically connected with the Baptism story: without the first, you cannot have the second, et vice versa.
This says us that the entire baptism + temptation story is so elaborated, that the suspicion is again raised about the possibility that the entire effort was made to react against *Ev.
Mark and *Ev agree about Jesus entering as a god in Galilee.
Where they diverge:
- *Ev makes Jesus enter in Galilee as an unknown god.
- Mark makes Jesus enter in Galilee as a known god: the god made known by the entire baptism of Jesus by John the Baptist.