The vedic literature does not distinguish between the worship of siva or visnu. If we carefully go through the rituals which are totally veda-based, the names Vishnu and Shiva would occur almost indiscriminately without any connotation of the forms denoted by the two names today. Whether it is Shiva or Vishnu it refers only to the Supreme God - this is the intent of the vedas. 'He is Brahma, He is Siva, He is Hari (Visnu), He is Indra, He is the immortal, the Supreme lord of all,' says Narayana sukta. PURUSHA SUKTAM
Among the Vedas, the Purusha sukta is held in the highest esteem as it forms an integral part of each of the four vedas. The Purusha suktam is seen earliest in the Rgveda, as the 90th suktam of its10th Mandalam, with 16 mantrams. Later it is seen in the Vajasaneyi samhita of the Shukla Yajurveda, the Taittiriya samhita of the Krishna Yajurveda, the Samaveda, and the Atharvana veda, with some modifications. It is also referred to in Smritis, Itihasas, Puranas and Agamas.
SAHASRASHEERSHA PURUSHAH SAHASRAKSHAH SAHASRAPAT SA BHOOMIM VISHWATO VRTTVA ATTYATISHTHAT DASHANGULAM
Whatever has been and whatever is to be is all Purusha. He is the ruler of immortality and He appears to grow immensely through food. Three quarters of Him remains above (unmanifested). One quarter of Him has manifested here. with that He pervades all the living and the non-living.
By knowing Him alone does one cross beyond death, there is no other way of going over there.
Purusha sukta tells us that a sacrifice was conducted by Devas through thought in which they also sacrified the ever shining Purusha. Brahma was made as the sacrificial cow.From that sacrifice called "All embracing", the chants of Rigveda, Samaveda and Yajurveda were born. Animals came out from that fire. When the Purusha was made by their thought process by the devas, how did they make his limbs? How was his face made? Who were made as His hands? Who were made as His thighs and feet?
BRAHMANO ASYA MUKHAMASEED BAHOO RAJANYAH KRUTAH UROOSTADASYA YAD VAISHYAH PADBHYAM SHUDRO AJAYATA
His face became Brahmins, His hands were made as Kshatriyas, His thighs became Vaishyas, and from His feet were born the Shudras.
CHANDRAMA MANASO JATAH CHAKSHUH SURYO AJAYATA MUKHAD INDRASH CA AGNISH CA PRANAD VAYURAJAYATA
From His mind was born the Moon; from His eyes was born the Sun; from His face was born Indra and Agni; from His soul was born the Air. All the worlds were made just by his holy wish. Then the devas worshipped the Purusha, through this spiritual Yagna. And that Yagna became first among dharmas.
The Narayana suktam is a hymn in Yajurveda, in praise of Lord vishnu, which is one of the most important hymns in the vedic rituals. some commentators see it as a mystical appendix to the Purusha sukta.
Narayana sukta describes His form as having thousand heads, thousand eyes, and thousand limbs:
SAHASRASHEERSHAM DEVAM VISHWAKSHAM VISHWASHAMBHUVAM
Narayana is not merely the Father or creator of the Cosmos, but is also hidden in the hearts of everyone.It is indicated in the sukta: 'Narayanam mahajneyam' which means He is the Supreme object of being known.Further it says:
The Lord Narayana is the Supreme Absolute; Narayana is the Supreme Reality; Narayana is the Supreme Light; Narayana is the Supreme Self; Narayana is the Supreme Meditator; Narayana is the Supreme Meditation.