1 Mantra – Lyrical chants adoring the beauty of the Nature
2 Brahamanas – This section details about conducting Rituals.
3 Aranyakas – Prescribing various method of subjective worship – Upasana
4 Upanisads – Declaring the highest philosophical truths
Mantra: - This section of Vadas contains verses in form of mantra. These mantras are expressed in lyrical poetry. This lyrical poetry contains ecstatic admiration of the beauty and splendor of nature. The seeker who followed the mantra portion merely viewed and admired the natural powers as manifestations of the supreme reality.
The four classifications in each of the Vedas are according to the four stages of a human being’s intellectual development; which are; Age of Gazing, Age of Observation, Age of Scientific Inquiry and Age of Contemplation. Now Mantra; which is the first portion of Vedas reflects the ‘Age of Gazing’, since the seeker who followed this portion confined them to mere ‘Gazing’ and admired the phenomenon of nature.
Brahamanas: - The Brahamanas is the bulkiest portion in each Veda. They are commentaries on four Vedas detailing the proper performance of rituals. It is one step ahead of Mantra. Brahamanas express confidence in the infallible power of the mantras. The rituals and sacrifices (Karma-Kand) explained by Brahamnaa are the disciplines for the physical personality of human beings. One physically begins worshiping the great power, which one had merely admired earlier during the mantra stage. The Brahamana hold the view that, if expressed correctly, the texts will not fail.
Now on comparison of section of brahamana with the various stages of development of human intellect. As human intellect developed, mere gazing evolved into observation of the transcendental Reality in the terrestrial phenomena. As a result of this, human beings began to physically worship the great powers as evident in the brahamana portion.
Aranyakas: - The word ‘Aranyaka’ is dericed from ‘Aranya’, which which literally means forest or garden. Vedic rites like sacrifices are to be performed by householders (Grastha) living in a village. But after his mind get purified through such rites, he goes to a forest as a recluse to engage himself in meditation. It is to qualify for this stage of vanaprastha, to become inwardly pure and mellow. The name is given to this portion of the Vedas because spiritual seekers generally retired to quiet gardens or wooded country and mentally worshipped Reality without physically performing the rituals. Such mental worship is called ‘upasana, which forms the subject matter of the Aranyakas.
They explain the hidden meaning of Vedas; their metaphysical passages. Indeed they through light on esoteric message of our scripture. For the ‘Aranyakas’, more important than the performance of sacrifices awareness of their inner meaning and significance.
With still further development of the intellect observation gave rise to enquiry, and seekers retired to the quietude of the woods and mentally worshipped the same transcendental Truth. This marks the entry into the ‘Aranyaka’ portion.
Upanisads: - Upanisads declares the highest philosophical truths. The Upaniñads constitute the concluding portion of the Vedas, which is also called ‘Vedanta. ‘Anta’ means end and ‘veda’ means knowledge. This portion satisfies the intellectual demands of an individual. It rationally explains Godhood, religion and its injunctions and is replete with philosophical wisdom of the highest order.
The Upanishads are considered by orthodox Hindus to contain revealed truths concerning the nature of ultimate reality and describing the character and form of human salvation.
The Sanskrit term ‘Upanisad’ derived from Upa- (nearby), ni-(at the proper place, down) and sad (to sit) thus “sitting down near”, implying sitting near a teacher to receive instructions or sitting at the foot of a qualified teacher to rest ignorance by revealing the knowledge of the supreme spirit.
The final stage in the development of the human intellect was the Age of Contemplation. At this stage human beings began to inquire into the very Cause of the universe and tried to identify the omnipotent, omnipresent, and omniscient Truth—God. This great search for Reality forms the subject matter of the Upanisads which is also called Vedanta.