There is an interesting story in the Mahabharata of Arjun unsuccessfully attempting to stop the disappearance of the new born children of a Brahmin couple. The story is associated with the symbolism of Nara Narayana concept.
Once an anxious Brahmin approached Arjun and appealed him to save him from a strange phenomenon. All the children that were born to the Brahmin and his wife vanished without a trace.
Now his wife was again pregnant and he wanted Arjuna to save his child from the strange affliction.
Arjuna promised to save the child. Arjuna was so confident about this strength that he would fight Yama, the god of death himself to rescue the child. He also declared that if he failed to save the child then he will burn himself.
Krishna who was watching the event from a distance volunteered to join in the endeavour.
Arjuna built a tight barricade with arrows and stood guard at the door. The woman went into labor inside the barricade.
A few minutes later he heard the cry of a baby. But soon there was silence and the Brahmin cried out the baby has disappeared.
Unable to face failure and wracked by guilt, Arjun decided to end his life.
Sri Krishna intervened and asked Arjuna to come with him on his chariot.
It was a journey through strange places. Soon, Arjun realized that the chariot was not touching the ground.
They were traveling through dark sky and the path was lit by whirling Sudarshan Chakra of Krishna.
Arjuna witnessed numerous worlds with numerous different types of creatures. The surrounding and environment kept changing. Finally they arrived at ksheera sagara, the milky ocean.
Here Arjuna had the vision of Lord Vishnu lying on the thousand hooded serpent Adi Ananta Sesha along with Goddess Lakshmi. He saw Goddess Saraswathi, the goddess of learning, sitting on the tongue of Vishnu.
Tears trickled down the eyes of Arjuna, he fell at the feet of Vishnu. When he stood up, he saw the missing babies of Brahmin playing around Vishnu.
Krishna then told Arjuna the reason for bringing Arjuna this far.
Krishna told Arjuna that they were Nara and Narayana and together they restored Dharma in various yugas. In Dwapara Yuga, they are Arjuna and Krishna.
Krishna is wisdom and Arjuna is action. One without the other is meaningless. Battles are only won when Nara and Narayana are together.
True wisdom and right action are necessary for success in all endeavors on earth.
Arjuna now realized the truth. Both Krishna and Arjuna then returned to earth with the babies of the Brahmin couple.