As the mistake was carried out with the god Indra, he grants Hanuman a would like that his body will be as robust as Indra's Vajra, and that his Vajra can also not damage him. Coupled with Indra other gods have also granted him needs: the God Agni granted Hanuman https://www.tumblr.com/hanumanmandiradelaide/775735432936816640/the-significance-of-lord-hanuman-and-his-spiritual?source=share