The main aim of all four vedas is to preach about attainment of salvation by worshipping God while following the eternal Vedic path. Yet, Rigveda especially tells about knowledge (Gyan kand). God has given detailed description about all matters. (Materialistic/worldly matters like science etc., with its qualities/attributes and nature. For example-
Qualities of sun, moon, water, trees including each matter of the universe).
Yajurveda tells about form of deeds. Pious deeds which should be done and not the sins.
Main description in Samveda is about the eternal worship of God like Yajyen, name jaap and Ashtang yoga. Followers of the said worship done under guidance of learned acharya, sure realise God and thus attain salvation.
Atharvaveda especially preaches about medical science and also states that above quoted three educations in the Vedas are true.
First mantra of Rigveda states about ‘Agni’. Mantra is as under-
The meaning of devta is “Subject” of the mantra.
“AGNIMEEDEY PUROHITUM YAJASYA DEVAM RITVIJUM HOTARUM RATNADHATAMUM”
(RIGVEDA MANTRA 1/1/1)
The mantra is in “Shlesh alankar” therefore, signifies two meanings of word- Agni. First is Almighty God and second is corporal/material (Agni)fire.
Meaning and idea of the above quoted mantra in respect of Almighty God is as under-
(AGNIM) Almighty, Formless God (EEDEY) to worship/to praise (YAJASYA) of Yajyen (HOTARUM) bestower/giver (PUROHITUM) who holds the entire universe before as well as after the creation, that is God is the supreme benefactor of souls and Prakriti after final destruction also. (RITVIJUM) adorable and worshippable in every season (RATNADHATAMUM) holder of all precious gems, gold etc. (DEVAM) bestower/giver i.e., giver of all precious gems, gold and other necessities.
Meaning- I worship the God who is bestower/giver of yajyen, He is our Purohitum i.e., Purohit which means that God only holds/protects the souls and non-alive Prakriti after final destruction. He also nurses us after creation. He is Ritvijum i.e., adorable and worshippable in every season. He is Ratnadhatamum i.e., holder of all precious gems, gold etc., and He is Devam i.e., bestower of the said precious gems and other necessities which include clothing, shelter, food, crops, water, air etc., to survive.
Idea- Yajyen means Devpooja, Sangatikarann and daan. Devpooja means the services rendered to five devas. Sangatikarann means to satisfy the learned acharya of vedas and yoga philosophy by rendering services towards him, at level best so as to get Vedic education in return. Daan means to donate to authentic person. So the idea of the mantra is that we the human-beings must worship/praise only one God possessing the divine qualities mentioned in the above quoted mantra.
If we worship a God who does not possess the above stated divine qualities like possessing power of creation, nursing, destruction of universe etc., then our worship does not tally with the eternal knowledge of vedas and hence the problem arises.
We must also note that the above divine qualities are possessed only by formless, omnipresent, Almighty God equivalent to whom no one was born, is born or shall ever be born in future. So, God was one, is one and shall always remain one. He is lord of universe. We all must worship Him only.