Let us try to understand Gurbani with an open mind or else logically we will be lost. Like can we go and enquire from brahma, narad, author of ved etc as is being instructed, 'ਪੂਛਹੁ ਬ੍ਰਹਮੇ ਨਾਰਦੈ ਬੇਦ ਬਿਆਸੈ ਕੋਇ ॥੧॥ ਰਹਾਉ ॥ or is their any need when gurbani tells us, 'ਭਾਈ ਰੇ ਗੁਰ ਬਿਨੁ ਗਿਆਨੁ ਨ ਹੋਇ ॥ without introspection manh cannot be enlightened and then transformed, thus naturally these brahma, narad are no one but our indray gian indray. Guru Nanak had to start from where his audience was. The mythological concepts (Naad etc) and figures (Shiva, Vishnu, Brahma, Krishna etc) were all well ingrained in the mind of those who were seeking spiritual guidance from guru sahib. Use of above vocubalry was essential for effective communication. i.e. why he opened up and clarified in Japjisahib:
ਗੁਰਮੁਖਿ ਨਾਦੰ ਗੁਰਮੁਖਿ ਵੇਦੰ ਗੁਰਮੁਖਿ ਰਹਿਆ ਸਮਾਈ ॥
The Guru's Word is the Sound-current of the Naad; the Guru's Word is the Wisdom of the Vedas; the Guru's Word is all-pervading.
ਗੁਰੁ ਈਸਰੁ ਗੁਰੁ ਗੋਰਖੁ ਬਰਮਾ ਗੁਰੁ ਪਾਰਬਤੀ ਮਾਈ ॥
The Guru is Shiva, the Guru is Vishnu and Brahma; the Guru is Paarvati and Lakhshmi.
For the spotless, truthful mind of oneness, divine message of nijhghar is naad and non-stop hearing and practicing is anhad naad. For him sach da gian is ved and further says its order pervades all over. For the manh imbibed in the divine court of nijghar, satguru is ishvar, the essence (tat-gian) is gorkah. In that state of mind whatever divine virtues emanates is brahma and in that process the descriminatory intellect transformed is (parbhati maey - bheebek budhi).
So in above two sentences he clarifies in fact our sensory organs are real bhrama, vishnu, sarsvati, parbhati maey and calls for introspection as real puja. I once again repeat as Gyani jee has said "words" used may LOOK SIMILAR...but they DONT MEAN the SAME. We can quote symbolically the religious text but not condemn or estimate and which I feel was not the mission of guru sahib. Therefore I suggest let us interpret gurbani with gurbani.