As the mistake was accomplished by the god Indra, he grants Hanuman a wish that his entire body might be as strong as Indra's Vajra, and that his Vajra could also not damage him. In conjunction with Indra other gods have also granted him wishes: the God Agni granted Hanuman https://www.tumblr.com/hanumanmandiradelaide/747945667911122944/a-pinnacle-of-hindu-worship-in-adelaide