ās said in nārāyaṇa sūktham -sa brahmā sa ṣivassĕndhra:- (he [bhagavān] is brahmā, he is ṣiva, he is indhra), bhagavān who is the ṣarīrī (āthmā) of brahmā, rudhra and indhra, [yet] they are seen as himself —

having the three forms of brahmā, vishṇu and ṣiva —

 ḥaving the forms of brahmā, vishṇu and rudhra —