As the error was accomplished from the god Indra, he grants Hanuman a want that his entire body could well be as solid as Indra's Vajra, Which his Vajra might also not hurt him. Together with Indra other gods have also granted him needs: the God Agni granted Hanuman a https://medium.com/@jameag789/discover-the-essence-of-hinduism-at-the-hanuman-mandir-68de16496046