Some people said that Lord Shiva is the main God of Hinduism and people said that Lord Vishnu is the main God in Hinduism. So,who is the actually the main God? Is it Lord Shiva or Lord Vishnu?
If one God was to be the main God then believe me there would have been exactly one & not so many.
It is is said that in the beginning(prior to creation) when nothing existed then there was only one Supreme being that still existed.He is who we call the Para Brahman.Then he had an urge to create and thus he created out of himself the Goddess first,called the Para Shakti,ideally the female counterpart of Para Brahaman.
The Para Brahman also divided himself into three beings(trinity) viz-Brahman,Vishnu and Mahesh(Shiva).So ,the Trinity are nothing but three aspects of the Para Brahman.
So ,now you understood who among Lord Vishnu and Lord Shiva is superior?
It is repeatedly condemned in scriptures not to differentiate between the Trinties,Doing so is a grave sin in itself.
"Sivasya Hrudayam Vishnor,Vishnuscha Hrudayam Sivaha" meaning Vishnu is the heart of shiva and Shiva is the heart of Vishnu.They are the two aspects of Para Brahaman and in truth ,as the self realised saints have said, infact one.
EDIT-Adding further references from scriptures that show the the Trinity is in fact one and an indivisible entity.There is no difference between them and thus the question of superiority/inferiority(between Vishnu & Shiva in particular) doesn't arise.
Reference 1.From the Varaha Purana:When Lord Krishna's wife Jambavati wanted to beget a son like Indra , Lord Krishna once did a penance and worship of Parama Shiva to fulfill her that wish.
Shri Krishna eulogised Parameswara and fell on the feet of Shiva-Parvatis. As a gladdened Parvati was enjoying Krishna’s visit, Parama Shiva embraced Krishna and said: Krishna! You are indeed the bestower of wishes to one and all yourself! Krishna smiled and said that they knew indeed whatever he approached them for; but the boon that he sought was to bless him to secure a son as renowned as Maha Deva himself! As both Shiva and Parvati granted the wish, Shri Krishna visitited Kailasha for enjoyment and rerturned to Dwaraka. .. Consequent to Shiva Darshana, Krishna was blessed with the birth of Saambu from Devi Jambavati.
Maharshi Markandeya wondered as to why Krishna who himself was worship-worthy and granted boons to his devotees needed to worship Shiva, Krishna replied smilingly:
Markandeya! Whatever you said is in order and the Truth is that I am worship-worthy by others; but still I worship Ishaana; there is nothing that I cannot achieve a thing, nor is unavailable to me; yet I am aware that I perform Puja to Parama Shiva. Those who are unable to overcome Maya or Illusion could never achieve Shiva Darshana; but I do realise that my foundation is Shiva and hence I always worship Him. There is no better Punya Phala nor fearlessness than what the Sacred Task of Lingaarchana would confer and for accomplishing propitiousness human beings must resort to Shiva Puja, Shri Krishna affirms. Those who realise and experience Vedic Siddhaantaas (Principles) do recognise that Shiva Linga is my own Swarupa and that is precisely why I perform my own worship of the Atma Swarupa of Ishana, says Krishna. He further confirms: I am Shankara’s Parama Murti and I am Shankara myself without doubt. Vedas have emphasised that there is no differernce whatsoever and Krishna and Shiva are just the same. This is the reason why that one should instal Shiva Linga all over!)
Reference 2.From the Kurma Purana:
Singularity of Tri Murthis
Depending on the emphasis of the Satwa-Rajas-Tamasa Gunas of the Eternal and Unique Paramatma, three Murtis were formed as Brahma-Vishnu and Maheshwara:
Tistrastu Murtayah prokta Brahma Vishnu Maheswaraah,
Rajah Satwa Tamoyogaat Parasya Paramatmanah/
Anyonyayamanuraktaastey hyanonyamupa jeevinah,
Anyonyam pranataashchaiva leelayaa Parameshvaraah/
Braahmi Maaheshwari chaiva tathaivaakshara bhavanaa,
Tristrastu Bhavana Rudrey vartantey satatam Dwijaah/
Pravartatey mayyajastramaadyaa chaakshara bhaavanaa,
Dwitiya Brahmanah proktraa Devasyaakshara bhaavanaa/
Aham chaiva Maha Devo na bhinnou paramaarthatah,
Vibhajya swecchhayaatmaanam sontaraameshwarah sthitah/
Ttrailokya makhilam Srushtim Sadevaasura maanushaam,
Purushaha Paratovyaktaad Brahmatwam samupamagat/
Tasmaad Brahmaa Mahadevo Vishnurvishweshvarah Parah,
Ekaikssyaiva Smritaastitrastanuh Karyavashaat Prabho/
Tasmaat sarva prayatnena Vandyaah Pujyaah prayatnatah,
Yadicchedachiraat sthaanam yattanmokshaakhya mavyayam/
(Paramatma materialised Trimurtis on the basis of Satwa-Rajo-Tamo Gunas for the three basic responsibilities of Srishti-Sthiti-Samhara; the Three Profiles are dependent on each other, transferable to each other, interested and involved with each other in fulfilling their tasks; they also greet each other, exchange and also supplement each other’s thoughts and deeds. Indeed they are indivisible. Also, Rudra is interactive with the inherent thoughts of Brahmi, Maheswari and Akshara / Vaishnavi. From his side said Bhagavan Vishnu / Kurma Deva that the thoughts of ‘A’kshara were spontaneous and of the second Letter of the word Akshara denoted Brahmi and so on. As far as Vishnu and Maheshwara were concerned there indeed was no duplication whatsoever. They were mutually and freely exchangeable, divisible yet wholly singular, mystifying and confusing and were indeed one and the same. It was the same Swarupa of Bhagavan who was like all the three who were close-knit! Indeed all three Murtis are worthy of worship and thus the need for attaining any one of them is similar to realise them all.
Reference 3. From Kurma Purana again:
Re-emphasis on the Oneness of Shiva-Narayana: In the context of the above, Maha Deva emphasised again as in earlier pages about the identity of himself and Vishnu Deva; this was necessary since a seperate ‘Ishwara Gita’in the current Kurma Purana sought to clarify that its contents were in no way contradictory ; even in the description of Shiva Tandava described above, Vishnu too was stated to have joined the Celestial Dance! Maha Deva thus confirmed as follows:
Ayam Narayano yohameeshwaro naatra samshayah,
Naantaram ye prapashyanti teshaam Devamidam param/
Mamaushaa Paramaa Murtirnaaraayana samaahvayaa,
Sarva Bhutaatmabhutasthaa Shantaa chaakshara sangjnitaa/
Ye twanyathaa prapashyanti lokey bheda drusho janaah,
Na tey maam samprapashyanti jayentey cha punah punah/
Yetwimam Vishnu – mavyaktam maam vaa Devam Maheswaram,
Ekibhavena pashyanti na teshaam punarudbhavah/
Tasmaadanaadi nidhanam Vishnumaatmaanamayayam,
Maameva samprapashayadhvam Puja-yadhvam tathaiva hi/
Yenyathaa maam prapashyanti matvemam Devataantaram,
ye yantin Narakaan ghoraan naaham teshu vyavasthitah/
Murkham vaa Panditam vaapi Brahmanamvaa madaasrayam,
Mochayaami shvapaakam vaa Naaraayana nindakam/
Tasmaadesha Maha Yogi Mad Bhaktaih Purushottamah,
Archaneeyo Namaskaarye Matpreeti jananaaya hi/
( That Narayana is Ishwara that is me undoubtedly. There is indeed no difference between us and he too is to be worshipped. Narayana is ‘Shaanti-Akshara’ imprinted in every body’s heart. Some imagine otherwise that we are figured other wise and they continue to get into the cycle of birth and death and could never ever attain Mukti. Those who visualise me and Narayana as just the same would have no rebirth. As such, Vishnu has no beginning or end as in my case, meaning thereby we are both the same. Those who confuse Vishnu as another Deva would for sure reach Narakas. Those who are my bhaktaas being either Murkhaas or Stupids, Panditas or Learned Vidvans or even untouchables should indeed have the possibility of Mukti, provided they do not dislike or distrust him. Hence my bhaktaas ought to perform puja to Vishnu with all humilty and belief.) Then both Vishnu and Shiva disappeared simultaneously, stated Vyasa Muni.