As the error was completed because of the god Indra, he grants Hanuman a desire that his body could well be as strong as Indra's Vajra, Which his Vajra might also not damage him. In addition to Indra other gods have also granted him wishes: the God Agni granted Hanuman https://hanuman-shabhar-mantra40245.mybuzzblog.com/16871004/beej-mantra-no-further-a-mystery