As the error was done from the god Indra, he grants Hanuman a want that his overall body could well be as potent as Indra's Vajra, and that his Vajra may also not harm him. As well as Indra other gods have also granted him needs: the God Agni granted https://indiantempleadelaide.health.blog/2024/06/14/discover-the-essence-of-hinduism-at-the-hanuman-mandir/