In Deathly Hallow, when Voldemort
kills Harry,
Harry does not resist the spell.
When Harry was in King's Cross, Dumbledore says that it was important that Harry did not resist the spell.
Why did Dumbledore say that? What were the implications of Harry not resisting?
There are three effects of Harry not resisting Voldemort. Two were certain, one is a good guess:
First of all, it ensured that when Voldemort finally died, he died for good, with no Horcruxes remaining.
If Harry did resist Voldemort, Voldemort would not have been able to "kill" Harry - the same way Voldemort could not kill Harry in the final duel.
The reason Voldemort lost the latter duel was because Harry was the master of the Elder Wand - and that was already true in the Forest scene. It had nothing to do with what happened in the forest.
Harry saw Voldemort’s green jet meet his own spell, saw the Elder Wand fly high, dark against the sunrise, spinning across the enchanted ceiling like the head of Nagini, spinning through the air toward the master it would not kill, who had come to take full possession of it at last
(Deathly Hallows, Chapter 36 - The Flaw in the Plan)
And if Voldemort didn't "kill" Harry, he wouldn't have destroyed the last piece of his soul that was latched onto Harry, thus rendering Voldemort immortal still - so even if Harry confronted him in a duel (like he did later on) and Voldemort's body was destroyed, his soul remaint would have again survived, due to having had his last "Horcrux" (yes, Harry wasn't a "real" Horcrux, but he did function as one for Voldemort's immortality purposes).
“I let him kill me,” said Harry. “Didn’t I?”
“You did,” said Dumbledore, nodding. “Go on!”
“So the part of his soul that was in me . . . ”
Dumbledore nodded still more enthusiastically, urging Harry onward, a broad smile of encouragement on his face.
“ . . . has it gone?”
(Deathly Hallows, Chapter 35 - King's Crosss)
The second effect was that Harry, by choosing to die instead of to fight (and protect his friends from Voldemort's threats), triggered the same kind of love protection magic that Lily's chosen sacrifice did for Harry.
“You won’t be killing anyone else tonight,” said Harry as they circled, and stared into each other’s eyes, green into red. “You won’t be able to kill any of them ever again. Don’t you get it? I was ready to die to stop you from hurting these people—”
“But you did not!”
“—I meant to, and that’s what it did. I’ve done what my mother did. They’re protected from you. Haven’t you noticed how none of the spells you put on them are binding? You can’t torture them. You can’t touch them. You don’t learn from your mistakes, Riddle, do you?”
(Deathly Hallows, Chapter 36 - The Flaw in the Plan)
This one is less certain, but it's possible that not resisting is what fully proclaimed Harry as the Master of Death, which may have affected Elder Wand's allegience in the end as well.
This is based on what Dumbledore said about the original contest between two phoenix-core wands:
Voldemort proceeded to attack you with a wand that shared a core with yours. And now something very strange happened, as we know. The cores reacted in a way that Lord Voldemort, who never knew that your wand was twin of his, had never expected.
“He was more afraid than you were that night, Harry. You had accepted, even embraced, the possibility of death, something Lord Voldemort has never been able to do. Your courage won, your wand overpowered his. And in doing so, something happened between those wands, something that echoed the relationship between their masters.
(Deathly Hallows, Chapter 35 - King's Cross)
The reason I think this was a likely side effect was because the effect #1 (killing the last "Horcrux") has already happened by the time Dumbledore and Harry spoke, yet Dumbledore used future tense when referring to the effects of Harry's choice:
“But . . . ” Harry raised his hand instinctively towards the lightning scar. It did not seem to be there. “But I should have died—I didn’t defend myself! I meant to let him kill me!”
“And that,” said Dumbledore, “will, I think, have made all the difference.”
(Deathly Hallows, Chapter 35 - King's Cross)
An additional possible side effect, similar to #3, was that Harry ensured that even if he was killed in the final battle, he would easily go on, like Dumbledore himself did:
“I think,” said Dumbledore, “that if you choose to return, there is a chance that he may be finished for good. I cannot promise it.
But I know this, Harry, that you have less to fear from returning here than he does.” (DH - Ch. 35)After all, to the well-organized mind, death is but the next great adventure (PS)
“Oh yes.” Dumbledore smiled at him. “We are in King’s Cross, you say? I think that if you decided not to go back, you would be able to . . . let’s say . . . board a train.”
“And where would it take me?”
“On,” said Dumbledore simply. (DH - Ch. 35)
While Voldemort doesn't know this, he accidentally
turned Harry into a Horcrux.
That, plus the prophecy, implied that in order to defeat Voldemort for good, Harry had to die
temporarily, thus "destroying" the second-to-last Horcrux left.
Concerning the "not resisting", it would have been pointless since Harry's Death was necessary. His dying without resistance also made Voldemort pretty overconfident (well, even more than he was before, anyway) and give his lengthy "surrender now, I killed your Harry without effort"-speech, which both actually encouraged the resistance and probably gave some additional time for
Harry to return to life
before going on to attack those who opposed him.
From what I understand, Lily's sacrificial love still protected Harry. I don't believe the Elder Wand, by itself, was strong enough to counteract that protection.
(especially since Voldemort wasn't even the wand's true master)
By not resisting, Harry is indicating that he is at peace.
and ready to die
By not protecting himself, the protection given to him through his mother did not apply
allowing Harry to "die".
