Why Lord Krishna saved Arjuna from Vaishnava Astra?

Question

• In mahabhartha arjuna was told to be saved from Vaishnava astra by Lord Krishna.
• A warrior named Bhagadatta used this astra against Arjuna, as Lord krishna stood up and the astra turned into a garland and fell on Lord Krishna.
  MY QUESTION :
• As Arjuna had Brahmastra, Brahmahasisthra, and the Pashupatastra (Special) why didn't he used it to stop it ?
• Is Vaishnava Astra Powerful than Pashupatastra or Brahmastra which made Lord krishna to stop it ?

Answer 1

In Mahabharata, Drona Parva (Book 7), SECTION XXVII, it was said by Lord Krishna that Vaishnava weapon is most powerful and unconquerable. It was the weapon given by Lord Narayana to Goddess Earth for the protection of Narakasura. Bhagadatta received that weapon from Narakasura. When Bhagadatta had used it against Arjuna, Lord Krishna came in between and the astra turned into garland.

Thus pierced, he was excessively pained. Filled then with rage, he with Mantras, turned his hook into the Vaishnava weapon and hurled it at Arjuna's breast. That all-slaying weapon, hurled by Bhagadatta, Kesava, covering Arjuna, received on his breast. Thereupon, that weapon became a triumphal garland on Kesava's breast.

Then Arjuna asked Lord Krishna that why he has done this because he himself was capable to neutralize that weapon but he was told by Lord Krishna that it was not possible by him.

Arjuna then cheerlessly addressed Kesava, saying, 'O sinless one, without battling thyself, thou art to only guide my steed! Thou hadst said so, O lotus-eyed one! Why then dost thou not adhere to thy promise? If I sink in distress, or become unable to baffle, or resist a foe or weapon, then mayst thou act so, but not when I am standing thus. Thou knowest that with my bow and arrows I am competent to vanquish these worlds with the gods, the Asuras, and men.' Hearing these words of Arjuna, Vasudeva replied unto him, saying, 'Listen, O Partha, to this secret and ancient history as it is, O sinless one! I have four forms, eternally engaged as I am in protecting the worlds. Dividing my own Self, I ordain the good of the worlds. One form of mine, staying on the earth, is engaged in the practice of ascetic austerities. Another beholdeth the good and the evil deeds in the world. My third form, coming into the world of men, is engaged in action. My fourth form lieth down in sleep for a thousand years. The form of mine which awaketh from sleep at the end of a thousand years, granteth, upon awakening, excellent boons to persons deserving of them. The earth, knowing (on one occasion) that that time had come, asked of me a boon for (her son) Naraka. Hear, O Partha, what that boon was. Possessed of the Vaishnava weapon, let my son become incapable of being slain by the gods and the Asuras. It behoveth thee to grant me that weapon. Hearing this prayer, I then gave, in days of old, the supreme and infallible Vaishnava weapon to the Earth's son. I said also at that time these words, 'O Earth, let this weapon be infallible for the protection of Naraka. None will be able to slay him. Protected by this weapon, thy son will always, in all the worlds, be invincible and crush all hostile hosts.'Saying, So be it! the intelligent goddess went away, her wishes fulfilled. And Naraka also became invincible and always scorched his foes. It was from Naraka, O Partha, that the ruler of the Pragjyotishas got this weapon of mine. There is none, in all the world, O sire, including even Indra and Rudra, who is unslayable by this weapon. It was for thy sake, therefore, that I baffled it, violating my promise. The great Asura hath now been divested of that supreme weapon. Slay now, O Partha, that invincible foe of thine, viz., Bhagadatta, enemy of the gods, even as I formerly slew for the good of the worlds, the Asura Naraka.'

_{Please note that this answer is based on Mahabharata and I don't want to demean any gods (though it may look like in first glance) including Lord Indra or Lord Rudra.}