Revākhaṇḍa ascribed to the Vāyupurāṇa (RKV) 227.8

227.8

yathā hi puruṣe devas traimūrtatvam upāśritaḥ /
brahmaviṣṇumaheśākhyaṃ na bhedas tatra vai yathā /
tathā sarittraye pārtha bhedaṃ manasi mā kṛthāḥ //

For just as the Lord, assuming a threefold form in the Supreme Person,
is named Brahmā, Viṣṇu, and Maheśa, and there is indeed no difference among them,
even so, O son of Pṛthā, do not conceive any difference in your mind regarding the three rivers.