As the mistake was carried out by the god Indra, he grants Hanuman a wish that his system could be as robust as Indra's Vajra, Which his Vajra might also not harm him. Coupled with Indra other gods have also granted him wishes: the God Agni granted Hanuman a desire https://hanuman-shabhar-mantra24308.dailyblogzz.com/37499372/fascination-about-hanuman