Originally posted by: Chinappa
Hanuman is ansh avatar of Mahadev and only with his help can Ram defeat or kill Ravana. Thanks to Narada's curse to Vishnu that a vanar will come to his rescue and help him defeat or kill his enemy. Once narada realises that his mistake of cursing Vishnu, he apologises to him but Vishnu is happy that he cursed because only Mahadev can help him and he is the one who would come in Hanuman (ansh avatar) avatar to his rescue.
Whether it is Ramayana or Mahabaratha, Mahadev and Vishnu's role is very pivotal, without them it would've never got over. In Mahabarath when Krishna chooses to be the sarathy, Hanuman voluneteers to guard the chariot in the form of symbol on the flag. Hence it was because of Vishnu and Hanuman that Arjuna was victorious.
What caused Narad to curse Vishnu...pardon my ignorance ...