"Maybe Dumbledore Saved His Life..."

With some help from my mom, I've just thought of a theory about Harry Potter and the Deathly Hallows. I was discussing with my parents why Dumbledore trusted Snape and whether or not Snape is a good guy. My mom suggested that maybe Dumbledore saved Snape's life.

This led me to think that if Dumbledore did save his life, then Snape would have a life debt to him. This would mean that there wouldn't need to have been an unbreakable vow between them in order for Snape to do something that Dumbledore wanted, perhaps to kill him. This is important because if Dumbledore always trusted Snape, as he said he did repeatedly, then he would not have made an unbreakable vow with him. Unbreakable vows are only really useful as a way to force somebody to do something that you don't trust them to do.

Maybe Dumbledore trusts Snape because he knows that Snape has a life debt to him, and that Snape feels compelled to honor his life debts, such as he did by trying to save Harry in an attempt to even his life debt with his father, James. And thus MAYBE, when Dumbledore speaks of the usefulness of life debts to Harry, he is referring not only to Peter Pettigrew's debt, but also to Snape's life debt to him, which he knows will come in handy in the future.

In POA, Dumbledore says to Harry: "When one wizard saves another wizard's life, it creates a certain bond between them... and I'm much mistaken if Voldemort wants his servant in the debt of Harry Potter." He probably wouldn't want Snape, whom he sees as his servant and spy, to be in the debt of Dumbledore either. He goes on to say, "This is magic at its deepest, its most impenetrable, Harry." The deep, impenetrable nature of life debts is thus very similar to the nature of unbreakable vows.

I don't know if anyone has come up with this before, but I've listened to almost all the episodes of Pottercast and Mugglecast and I don't recall ever hearing anything about it.

Let me know what you think!