As the error was completed through the god Indra, he grants Hanuman a desire that his overall body would be as robust as Indra's Vajra, Which his Vajra also can not damage him. Together with Indra other gods have also granted him needs: the God Agni granted Hanuman a want https://hanuman-shabhar-mantra41826.blogoxo.com/37288642/everything-about-hanuman