why Snape wanted to teach DADA at first? Why Dumbledore didnt let him?
Seeing as the dark arts and everything related to that field was the cause of Lily's death, why would he even WANT to get involved with it again? Dumbledore was afraid of him being enticed and going down that path again if he were to teach it; but, if he loved her so much, आप would think he would shun DA and everything it stands for. Not sure why DD would think he would go down that path again..
Severus was literally fascinated द्वारा the Dark Arts - one of the reasons that prompted his falling out with Lily.
Though Severus would have been the most proficient teacher in this matter Hogwarts had ever had, Dumbledore was too much concerned that the Dark Arts would lead Severus down into his old Dark and evil ways.
(The same had been true of Tom Riddle, who had sought the same position in the past. Dumbledore, who had seen clear in him, was not to leave such a position to someone that was not clearly tied to the Light.)
Moreover, let's do not forget that the position was cursed. Dumbledore did not wish to be separated from Severus, whom he needed. Only for Harry's 6th year, he knew that he would die, and Voldemort would take over the school right after that. So the curse would work (= Severus would stay only one साल in that position) but Dumbledore would not lose his right hand man and spy.
Which did not prevent Dumbledore to allow Severus to cover for Remus when he had his "little furry problem". It's incredible that the only moment when we see him teach DADA, was in PoA, not in HBP. I missed the scene where Severus could have made his speech about the Dark Arts !
He was obviously covering for Lupin. He enjoyed that occasion to draw the students' attention to Lupin being a werewolf. Whether वेयरवोल्फ were considered as Dark creatures, that's another issue.
^^In PoA, Hermione tells Snape (when he mentions they'll be learning about werewolves) that they just started learning about hinkypunks, and aren't meant to start learning about nocturnal beasts for weeks. That means that वेयरवोल्फ were on the agenda, regardless of whether Snape taught it या Lupin did.
Severus clearly states in Half-Blood Prince that Dumbledore wouldn't give him the DADA position because he "seemed to think it might, ah, bring about a relapse...tempt me into my old ways." And it would have. आप do not walk the Shadowed Path for years and then leave it entirely, regardless of the reason for departing it. Once आप step onto that Path, it becomes a part of आप forever. Oh, yes, आप can do Good in the world and for it, आप can प्यार completely and die for love, या give your life to protect innocent ones, but that does not clense आप of the stain. It just means आप truly know what you're up against when you're fighting it. The temptation to go back to that Path is always there, though the strength of that temptation would vary from individual to individual.
It sounds very much like a recovering addict--they have to deal with the temptation to drink/use drugs/gamble/whatever all the time, just as Snape has to fight his temptation to the Dark Arts. And just like an addiction, I wonder if the Dark Arts wasn't a mechanism to cope with and/or control his unfortunate environment?
@ojamajoyy: Not really, because he knows Dumbly is right, even though he does not want to admit it. @Filleirlandaise: Very good comparison, and yes, that's exactly why Severus got involved with the Dart Arts, coping and defence mechanism.
I'm not sure if we ever get a proper answer to this in the books, but we know that Snape had always had a fascination with the Dark Arts since his school days, so it's not too big a stretch to think his favourite subject would be DADA, even if he preferred the actual Dark Arts rather than Defence. I think the reason that Dumbledore didn't let him teach it is that it wasn't long after Snape had switched sides, and he was worried Snape might have a relapse and fall in प्यार with the Dark Arts again if he were allowed to teach DADA. I'm not sure though, this is just guessing. :)
Well I think Dumbledore cared about him just as he did for Harry and knowing he was a deatheater he knew if he were put as a teacher for DADA that it wouldn't be long before he would officially go dark and no longer work both sides
My thought is Dumbledore knew the Defence against the Dark arts was 'Jinxed'. If Snape Landed it in the 1st Place, something would have happened to him. Voldemort wanted the job And Dumbledore refused. So Voldy Jinxed it. Nothing happened to Snape in HBP, because Voldy too the curse off. He was under the impression Snape served him and not Dumbledore.
