"Dutifulness"
Korra knew people who had been willing to sacrifice themselves to save others.
Lin had risked her life and lost her bending to protect Tenzin and his family. Korra did not know whether this had been out of her care for them or her commitment to protecting people of interest. Maybe it was both. Or maybe it was neither: maybe Lin just wanted to protect people in danger, whoever they happened to be.
When Unalaq had threatened Jinora, she had selflessly urged Korra not to give in to his demand, because she knew her life was not worth compromising the safety of the world. Korra had been selfish when she chose to cooperate and open the spirit portal. She hadn't wanted to lose Jinora, her friend and surrogate sister; and she hadn't wanted to have to tell Tenzin that she'd chosen to abandon his daughter.
Lin and Jinora knew that they were relatively unimportant compared to the other stakes. The only ones who would have been hurt by their deaths were their own friends and relatives.
Korra's situation was different. If she disappeared, the whole world would suffer because of her absence. If she died, it would be years before the next Avatar grew old enough to take on the role of keeping balance. She knew this well enough from Aang's history. His disappearance had allowed a hundred years of war. His death had given criminals like the Triple Threat Triad and tyrants like the Earth Queen time to thrive while Korra grew into adulthood.
Lord Zuko had said, "In times of turmoil, the world needs its Avatar the most." With the Earth Kingdom in chaos, and the Red Lotus hunting down political leaders, people would need Korra to protect and defend them. Korra did not know whether the Red Lotus meant to take away her freedom or her life; but either way, they were sure to keep her from doing her work as Avatar. Would it be right for her to sacrifice herself for the sake of one nation, if it meant putting the entire world in jeopardy?
Korra knew that Aang would have made that choice, not just because it concerned the people he loved, but because it was the right thing to do. Too many innocent people had died in his stead during the Air Nomad genocide, and generations were killed during the Hundred Year War. If it was in his power to prevent deaths, he would do it.
Realizing this, Korra knew she had her answer. Yes, the world needed an Avatar. But, it also needed the Air Nation.
Korra was ready to die. At least, she tried to be. She and Raava were still connected, so the reincarnation cycle would continue, and she could guide future Avatars on their journeys. Maybe she would even be able to see her loved ones again, if they were able to find the next Avatar. She had always thought that she'd like her friends to train her next life, the way Aang's family had trained her. The next Avatar would be born in the Earth Kingdom, and Korra could imagine Bolin teaching earthbending, followed by Mako in firebending, and Jinora for airbending.
She didn't know what she appreciated more: that her friends and allies respected her decision, or that they still wanted to find a way to save her. But the latter made Korra more reluctant to surrender, less resigned to an unfortunate fate. The hope that her friends gave her made her want to live again.
Then, everything fell apart. Nothing went the way they had hoped.
Each side tried to double-cross the other. Korra's sacrifice seemed to be made for nothing, as the Red Lotus did not release the airbenders or even reveal where they were. They may have already killed them all.
So, with no leverage stopping her, Korra fought back. The platinum chains weighed her down, but she managed to jump and used her feet to bend the earth, push the air, and produce fire. When Zaheer tried to lead her onto the airship, her father appeared to knock him away. When she fell, Tonraq reached out to help her. He didn't just protect her; he gave her an opening to fight back. For the first time she could remember, they worked in sync, as equals. Again, Korra thought they could win. But taking turns attacking was the wrong thing to do.
When Korra awoke an hour or two after Zaheer knocked her out, the last thing she remembered was seeing Zaheer blow Tonraq over the edge of the cliff.
Her father was gone.
The airbenders might be dead, her father surely must be dead, her friends had walked into a trap and were probably fighting for their lives. And now Korra herself was suspended by chains, her limbs stretched painfully to their limits, unable to bend (except to breathe fire to a distance not far enough to burn her captors).
And now that they had her alone, Zaheer finally explained what they intended. They knew as well as she did that killing her would only reincarnate her, but they also knew the loophole to end that cycle: killing her in the Avatar State.
It was cruelly ironic for them to use her body's natural defense mechanism to end her. Her will to live would cause her death. Fighting had long been Korra's instinct, but in this case, should she fight to live, or to die?
If she could stave off the Avatar State, she would would die like any other human. So that was what she tried to do, even as the poison was forced painfully through her skin and into her bloodstream.
She wished that she could communicate with Raava the way Avatar Wan had. She wanted to tell the light spirit, Don't try to save me. Just let me die, so I can be reborn. You're the one who wanted an Avatar, after all. Don't let that be pointless! Don't let them destroy us both!
Instead of Raava, she saw everyone who had tried to hurt her in the past: Amon, Unalaq, Vaatu. In some part of her mind she knew they were not really there, but she could not stop hearing their taunts. They verbalized the self-doubt she had suppressed for so long, and urged her to give up. Let go. Let go. Let go. But she did not know whether they meant she should give in to death or to the Avatar State.
Vaatu was wrong about one thing: she was not weak. The Avatar State might be her greatest vulnerability, but it was also her greatest strength—and if she entered it, she could still use it.
She would die no matter what, but she could still fight back, at least until her body succumbed to the poison. She could destroy the Red Lotus so they would no longer threaten the people she loved.
When she gave herself up to the Avatar State, it was not vengeance or a survival instinct that fueled her fury: it was righteous anger. She was a battle spirit, a defender, a conqueror, a savior. She didn't care how much her human body hurt. She had to win this fight, for the sake of the world.
Author's Notes
I had the idea for this piece back when the Book 3 finale aired, but I saved it to post on the following Maundy/Holy Thursday. I was inspired by the song "Gethsemane (I Only Want to Say)" from Jesus Christ Superstar, Andrew Lloyd Webber's musical based on the Gospel narratives of the events leading up to Christ's Passion. If you haven't seen or listened to the musical, I recommend listening to that song either before or after reading this.
This comparison is not meant to be offensive to God or to anyone who believes in Him. I'm not trying to raise the Avatar to the level of a deity; I'm trying to show how Christ can be seen in stories that aren't explicitly Christian. Whether they were intentional or not, no one can deny that the two Avatar series contain biblical parallels. The core concept of a divine-yet-human being is the most obvious, but there are others that pertain more to stories from the Bible.
I wrote this piece to point out the parallels between Korra's sacrifice and the Paschal Mystery (the suffering, death, and resurrection of Jesus Christ). Korra and Jesus both spent time meditating, debating whether to give themselves up, and were comforted by spiritual beings (Iroh for Korra, an angel for Jesus, according to Luke 22:42-43). Both Korra and Jesus sacrificed themselves to pay a ransom to save the people they loved. The way Korra hung in the Red Lotus cave visually resembled Jesus hanging from the cross. Jesus felt forsaken by His Father, and may have been taunted by demons the way Korra's past foes taunted her. The way Tonraq held Korra visually resembled the pietà, the image of Mary cradling Jesus after his crucifixion. ("Pietas" is Latin for "dutifulness", hence the title of this piece). I imagine Tonraq and Senna feel the same mixture of protectiveness and resignation that Mary and Joseph felt watching Jesus grow into his dangerous, demanding vocation.
In short, the intense emotions we felt during the finale are what Christians (should) feel when contemplating Easter and the events that led up to it. Only, we should feel even more overwhelmed because we are a part of the story. Jesus sacrificed Himself as a ransom for our souls, just as Korra sacrificed herself to save the airbenders. What Tenzin said during Jinora's ceremony sounded just like something a Christian leader would say regarding Jesus: "There's no way we can ever repay her for all she's done. But we can follow her example of service and sacrifice." That is exactly what Christians (should) try to do.
If you have questions about biblical parallels, atonement, Christology or hypostatic union, you can voice them in a review or a message. I will answer them to the best of my ability. If I cannot answer, I can recommend writers whose works offer explanations much better than mine.