Who is the oldest form of god to be worshipped? Is it Lord Siva or Lord Vishnu or Goddess Shakthi?
The oldest form of god to be worshiped. The answer is none of the above. From the earliest Vedas down to the present, water has been regarded as the tangible manifestation of the divine essence. "In the beginning, everything was like a sea without light" (Rig Veda X. 129.3, also Rig Veda X. 121.8 and Satapatha Brahmana XI 1.6.1). Even today, one of the most common and simplest forms of worship is some vessel filled with water which represents the divine presence and can serve in place of a image. The water, during worship, is regarded as the pitha of the god. Vedic alters always have some vessel with water in it.
Nirguna Brahman cannot be the object of meditation or worship, but Saguna Brahman can. Many people repeat the following in the morning as their first prayer of the day, it is a hymn to God as the one Guru of the universe:
gurur brahma gurur vishnuh gurur devo mahesvarah; gurur-eva param brahma tasmai sri guruave namah.
akhanda-mandala-karam vyaptam yena caracaram; tat padam daristam yena tasmai sri gurave namah.
The guru is Brahma, the Guru is Vishnu, the Guru is the Great God Siva, The Guru alone is the Supreme Brahman, I salute Him, the holy Guru. Who pervades the universe, moving and unmoving, of undivided form, as the universe, Who reveals that state, Him I salute, the holy Guru.
After this prayer one can then do prayer and praise to one's Ishta Deva.
Swami Vivekananda says that after taking your seat, to first pray to all the prophets and saviors of the world and holy spirits in the universe to help you.
In formal puja, Ganesha is often worshiped first.
If you are a severe Advaitist, you can follow Swami Vivekananda's words: "Repeating the Om continually is the only true worship. It is not a word, it is God Himself."
There are many forms of GOD which came into existence with GOD Stories, One GOD in Hinduism is believed to be "Aadi" Who had no form, GOD Shiva, who is believed to be "Neerakar" and his form is accepted as "Jyotirlingam". This form is said to be the form of GOD before being "Sakar". Lord Vishnu told once that Shiva Linga is eternal origin of all things. Whatever we see is a tree from that seed.
There are many disputes between various sact, but Lord Vishnu him self declared Shiva's devotee in many avatars and Shiva declared Vishnu as his heart. In Krishna avatar he told that he is Shiva in Rudras in Shrimad Bhagwat Geeta, But both these forms are "Sakar" form. After they took birth these avatars were worshiped.
From the story of dispute between Lord Brahma and Lord Vishnu, all Hinduism people believe that Shiva and other trinity are manifestation of same GOD. and all them meditate upon each other. This trinity is everything to Hinduism. But Shiva Lingam is believed to be the form of GOD as "Neerakar" before being "Sakar", that is why Lord Vishnu in all his avatars worshiped Shiva Lingam only.
If Lord Vishnu gives an example of worshiping Shiva Lingam (Rameshwara,Gopeshwara etc.), in Hinduism worshiping Shiva Lingam is standard worship. Lord Vishnu is GOD and whatever he says is obviously true.
Shiva and Shakti are not different, they both are one considered as "Ardha Nareshwara", Worship of Shakthi came into existence when Shakti-Peethas came into existence, so it is also not oldest. Sati, the first incarnation of Shakthi, also worshiped Shiva Lingam only, so if gods worship shiva lingam then it should be the oldest.
Lord Vishnu is believed to be the most powerful GOD in Hinduism, and whatever Lord Vishnu says "Hinduism" is defined by that only. Lord Vishnu says worship is part of human life. If Lord Vishnu gives message to the world to worship Shiva Lingam then we have to obey him. Lord did not change oldest form of god to be worshiped even taking birth from Satiyuga to Kaliyuga, so he will not give wrong message. So worship of Shiva Lingam is oldest form of GOD.
Lord Vishnu after his manifestation heard the voice to do penance and started meditating upon "Om Namah Shivay", so do you think Lord Vishnu who started just after the moment he manifested and did that in all his avatars is wrong? There are many proofs and many Strotra sung by Lord Vishnu in many avatars. Even Lord Vishnu got "Sudarshana Chakra" from Shiva worship only.
Lord Rama said "No one can get me without worshiping Shiva Lingam, I give a boon that whoever with pure heart make Abhisheka of Ganga's water on this Rameshwara Mahadeva Jyotir lingam will get me after death for sure."
Even archeologist found many Shiva Lingam in different areas of earth. These proofs made Hinduism the ancient religion.
(1) From the Bhagavad Gita, the scripture accepted by all in the Vedic tradition we have the following information:
7.7 O conqueror of wealth, there is no truth superior to Me. Everything rests upon Me, as pearls are strung on a thread.
10.1 The Supreme Personality of Godhead said: Listen again, O mighty-armed Arjuna. Because you are My dear friend, for your beneﬁt I shall speak to you further, giving knowledge that is better than what I have already explained.
10.2 Neither the hosts of demigods nor the great sages know My origin or opulences, for, in every respect, I am the source of the demigods and sages.
This fact is also realized by the best student of Gita, i.e, Arjuna.
10.12-13 Arjuna said: You are the Supreme Personality of Godhead, the ultimate abode, the purest, the Absolute Truth. You are the eternal, transcendental, original person, the unborn, the greatest. All the great sages such as Nārada, Asita, Devala and Vyāsa confirm this truth about You, and now You Yourself are declaring it to me.
(2) Some people, due to various motivations and reasons, consider impersonal brahman as the Supreme but as per Lord Krishna in the Gita He is the basis for brahman. Brahman is one of his aspect. Brahman is superior to this material world and considered transcendental but He is personal Brahman superior to impersonal Brahman.
14.27 And I am the basis of the impersonal Brahman, which is immortal, imperishable and eternal and is the constitutional position of ultimate happiness.
Lord Krishna says in 10.2 that even big sages and gods cannot properly understand Him. So the big big swamis who lack devotion to Krishna are confused in proper understanding with their speculative ideas. We also find from Bhagavatam that even Indra and Brahma got confused and considered Krishna as a mere boy of a village and Krishna crushed their pride and helped them realize the Truth. Ofcourse these pastimes also happen because the great gods want to establish that Krishna is the Supreme. There is also the incident of Krishna fighting with Banasura and Lord Siva fights on the side of Banasura but being defeated and having realized who Krishna is He says:
10.63.38 You are the original person, one without a second, transcendental and self-manifesting. Uncaused, you are the cause of all, and You are the ultimate controller. You are nonetheless perceived in terms of the transformations of matter effected by Your illusory energy — transformations You sanction so that the various material qualities can fully manifest.
10.64.43 I, Lord Brahmā, the other demigods and the pure-minded sages have all surrendered wholeheartedly unto You, our dearmost Self and Lord
(3) However unless one has loving relationship and devotion to Krishna it is impossible to accept the above facts and tons of other information in the sastras. It takes a lot of humility and devotion to accept these facts and surrender to Him. The whole point of Bhagavadgita is to awaken our devotion to Him and surrender unto Him. Lord Krishna Himself says:
18.55 One can understand Me as I am, as the Supreme Personality of Godhead, only by devotional service. And when one is in full consciousness of Me by such devotion, he can enter into the kingdom of God.
Abandon all varieties of religion and just surrender unto Me. I shall deliver you from all sinful reactions. Do not fear.
And when we talk of worship of Krishna it is also applicable to His various personal manifestations such as Rama, Narasihma, Narayana and other Vishnu forms.
Krishna is nothing he is not god..god is only Rudra brahman let see vedic upanishad (svetasvatara upanishad), about Rudra brahman. The non-dual Ensnarer rules by His powers. Remaining one and the same, He rules by His powers all the worlds during their manifestation and continued existence. They who know this become immortal.
2 Rudra is truly one; for the knowers of Brahman do not admit the existence of a second, He alone rules all the worlds by His powers. He dwells as the inner Self of every living being. After having created all the worlds, He, their Protector, takes them back into Himself at the end of time.
3 His eyes are everywhere, His faces everywhere, His arms everywhere, everywhere His feet. It is He, who endows men with arms, birds with feet and wings and men likewise with feet. Having produced heaven and earth, He remains as their non-dual manifester.
4 He, the omniscient Rudra, the creator of the gods and the bestower of their powers, the support of the universe, He who, in the beginning, gave birth to Hiranyagarbha-may He endow us with clear intellect!(svetasvatara upanishad)
In all civilisations,people realize,at some point of time,that the Gods that they worship , are Imaginary,i.e., they are the product of Human Imagination.
It is then they realise ,that Sun God is the real,eternal God, and build temples to Sun God...But ,for some strange, unexplained reasons , the Civilisation collapses after that.
The people of Kalinga, built the Sun Temple at Konarka around 1250AD. After that the Kalinga Kingdom disintegrated.
The Egyptians built the temple of God Ra, the Sun God,towards the end of their civilization.
The Romans also buil a temple to God Mitra- the Sun God , towards the end of their civilzation.
The Chinese also built temples to the Sun God.
Meditating the self is the oldest form of worship and when the avidya or ignorance occupies one, then he sees himself as different than god and then he starts taking births and starts worshiping.
Trinity worship each other and its according to his own spiritual level one may worship satva (Siva) or rajo (Vishnu) or tamo (bramha) guna god.