Karna, Arjuna and their previous birth
The long time ago there lived a demon (asura) named as Dambhodbhava. He wished to become ever dying. For this, he prayed to the Sun God (Surya). Surya being pleased with his prayers and meditation appeared before him. Dambhodbhava asked God Surya to give him immortality (a boon to live forever).
But Surya couldn’t fulfill this demand. As anything or anyone who had taken a birth on this planet has to die. Surya offered him to ask for something else rather than this wish. Dambhodbhava thought for a while. Then he came up with a cunning request. And so he asked, the Sun god that he wishes to be protected by a thousand armors (protective shields).
Conditions put forward by Dambhodbhava:
In addition to his secondary wish. He laid down the following conditions, and asked for the same from Sun God:
1. A thousand armors can only be broken by someone who performs a deep meditation for about thousand years!
2. Whosoever succeeds in breaking the armor should die immediately!
Surya became very much worried. He knew that Dambhodbhava had performed a very dedicated and powerful meditation. So he is eligible to get the entire wish he had asked for. And Surya had a negative feeling about Dambhodbhava. That he was not going to use his powers for good purpose. However, having left with no choice, in the matter, Surya granted Dambhodbhava the wish he asked for. But deep down Surya was worried. He went to Lord Vishnu for help. He narrated the full story to Lord Vishnu. And Vishnu asked him not to get worried. And said that he would save the earth by removing a dharma.
That he was not going to use his powers for good purpose. However, having left with no choice, in the matter, Surya granted Dambhodbhava the wish he asked for. But deep down Surya was worried. He went to Lord Vishnu for help. He narrated the full story to Lord Vishnu. And Vishnu asked him not to get worried. And said that he would save the earth by removing a dharma.
Immediately after receiving the boon from God Surya, Dambhodbhava started to trouble people. People were scared of fighting with him. They escaped his presence at times. There was no possible way of defeating him. Anybody who obstructed his way was badly crushed by him. People started calling him Sahasrakavacha(one who has a thousand armors).
Murti, Dharma and their Children:
It was around this time that King Daksha. The father of Sati, Sati was the first wife of Shiva. Got his daughter, named Murti married to Dharma. Who was one of the ‘Manas putras’ of Lord Brahma(the God of Creation). The girl Murti had also heard a lot about Sahasrakavacha(Dambhodbhava). And she wanted to put an end to his disturbance. So she prayed to Lord Vishnu to come himself and help the people. Lord Vishnu pleased with her appeared before her and said:
‘I am pleased with your deep devotion! I will come and kill Sahasrakavacha! As you have prayed for me, you would be the reason for murdering Sahasrakavacha.’
Narayana and Nara:
Murti gave birth to twins. And named them Narayana and Nara. Narayana and Nara grew up in the ashrama in the deep forests. They became great devotees of Lord Shiva. The two brothers learned and perfected the art of warfare. The two brothers shared a strong bond and were inseparable. What the one thought for, the other was always able to finish the task. Both of them trusted each other very much. Therefore, they never questioned each other regarding anything.
As time passed, Sahasrakavacha started destroying the forest areas surrounding Badrinath ashrama. It was the place where both Narayana and Nara were staying. In the mean time Nara was meditating, Narayana went and challenged Sahasrakavacha for a fight. Sahasrakavacha looked at his calm eyes. For the first time since birth, he felt a fear building inside him, as he was aware of his boon.
Sahasrakavacha faced the attack of Narayana and was completely shocked. He found that Narayana was powerful and strong. And he got this power from the penance of his brother, Nara. As the fight proceeded, Sahasrakavacha realized that the deep meditation of Nara was giving Narayana much strength. As Sahasrakavacha’s first armor broke he realized that Nara and Narayana were for a purpose. They were just two persons having the similar souls. But Sahasrakavacha was not much worried. As he had lost just one of his armors. He watched it down as Narayana dropped dead, the minute one of his armors broke!
As soon Narayana fell down dead. Nara came running towards him. By his years of meditation and pleasing Lord Shiva, he had gained the ‘Maha Mritunjaya’ mantra. It was a special mantra which could bring a dead person back to life. Now Nara took over the fighting with Sahasrakavacha while Narayana meditated. After a span of thousand years, Narawas able to break, another armor and was dropped dead. While Narayana came and brought him back to life. This went on and on. Until 999 armors were broken down to pieces. Sahasrakavacha by the time realized that he could never beat the two brothers. He ran away seeking the safety of God Surya. When Nara approached Surya to give up on him. Surya didn’t since he was protecting his devotee. Nara cursed Surya to be born as a human for this act. And Surya accepted the curse for this devotee.
Rebirth as Arjuna and Karna:
All this happened towards the end of Treta yuga. Immediately after when Surya refused to part with Sahasrakavacha in the declining Treta yuga. The Treta Yuga ended and the Dwapara yuga started. To fulfill the promise to destroying Sahasrakavacha, Narayana and Nara were reborn but this time as Krishna and Arjuna. They carried themselves forward in the Dwapara Yuga.
Due to the curse, Dambhodbhava along with Surya’s ansh (part) within him was born as Karna. The eldest son to Kunti. Karna was born with one of armour as a natural protection, the last one left of left out of Sahasrakavacha.
Due to the presence of armor with Karna. Arjuna would have died. If Karna continued to hold the armour. So on Krishna’s, advise, Indra Deva (Arjuna’s father) went in avatar of a Brahmin sage. And in charity he asked the armor of Karna. Therefore, he got the last armor of Karna, much before the war begun.
As Karna was actually the monster Dambodbhav in his previous life. He led a very difficult life to pay for all the sins committed by him in his past life. But Karna also had part of Surya, the Sun God inside him, therefore, Karna was a hero as well! It was Karna’s good karma from his previous life that he had to be with Duryodhana. And took part of the all the evil things he did. But the Surya in him lighted him and made him brave, strong, fearless and charitable. It brought him the long lasting fame.
Therefore, after learning the truth regarding Karna’s pervious birth. The Pandavas felt sorry towards Kunti and Krishna for bringing sadness to them.