Traditionally, the epic narrative involves some level of powerful weapons with divine elements attached to them.  In The Ramayana, the weapons that Lord Rama is able to use help him fight the demon- king Ravana.  The need for such divinely powerful weapons only help to indicate how powerful Lord Rama's adversary is.  The purpose of such weapons helps to highlight how much of a challenge Lord Rama must face.  It is one in which some type of benevolence from the divine is needed.The message that might be trying to be conveyed here is that in order to defeat forces of evil, intensely powerful weapons will be needed.  Lord Rama's weapons come from the deities, themselves, and accordingly, in order for human beings to defeat the forces of evil that stand as adversaries in their own quest, divine faith, bhakthi, becomes the most powerful of weapons. Seeing Lord Rama with such weapons helps to convey the idea that the battle between righteousness and injustice and doing what must be done to see the former defeat the latter requires additional resources that the individual must seek from the divine in a humble manner that reflects bhakthi and submission.