As the error was done via the god Indra, he grants Hanuman a desire that his human body will be as powerful as Indra's Vajra, and that his Vajra may not damage him. Together with Indra other gods have also granted him needs: the God Agni granted Hanuman a desire https://mohini-mantra44219.tokka-blog.com/37272232/little-known-facts-about-hanuman