Within the Veda, we find two paths to spiritual perfection: the vedic-marga and the pancaratrika-marga. The vedic-marga, which includes Vedic mantras like the Brahma-gayatri, is based on the four original Vedas: Rg, Sama, Yajur, andAtharva. Each of these Vedas contains four parts:
1) Samhita – comprise a collection of all the verses in that particular Veda.
2) The Brahmanas – explain the history and the esoteric significance of the mantras and sacrifices. They describe the verses of the Samhitas and give some details about performing sacrifices. They are ritualistic and meant for householders living in the village. The Brahmanas contain the seeds of the knowledge that is systematically elaborated upon in the Sutras (i.e. Srauta, Grhiya, Dharma). The Srautas describe the basic obligatory Vedic rituals such as the daily agni hotra and the big public sacrifices. The Grhiyas explain the household rituals, especially the samskaras.
The Dharma Sutras explain the vamasrama duties. The Manu-samhita and other Dharma Sastras, which explain the Dharma Sutras, are more accessible to the ordinary people. All these sutras and sastras were composed by various great sages like Manu, Narada and Yajnavalkya. These writings tell how to do things and deal basically with the sensual or bodily plane of existence.
3) Aranyakas – reveal the hidden purpose behind all the Vedas and Brahmanas. The Aranyakas and the Brahmanas are similar, but the Aranyakas cover more esoteric aspects. The Aranyakas explain the metaphysical basis of the rituals described in the Brahmanas. In other words, the Brahmanas tell how to do a ritual, and the Aranyakas explain why a particular ritual is performed. Considered dangerous for ordinary householders, the Aranyakas were studied secretly in the forest. Hence the name Aranyakas which means "forest."
4) Upanisads – give the philosophical meaning behind the verses and rituals. The Brahmanas, Aranyakas, and the Upanisads are all based on the Samhita.
A brahmacari will concentrate his studies on the Samhitas. A grhasta will focus on the Brahmanas, which instruct him how to move in the material world in a proper peaceful way. A vanaprastha will develop detachment by studying the Aranyakas to understand what he has done all his life. A sannyasi will read the Upanisads in order to rise to the transcendental platform and ultimately enter the spiritual world. Of course, all the asramas study all four parts, but they will emphasize one of the four according to the needs of their particular asrama.
The vedic-marga is basically a favorable, pious process that becomes transcendental at the level of the Upanisads, whereas the pancaratrika-marga is a completely transcendental process emphasizing Deity worship and the practice of sadhana bhakti.
Srila Prabhupada explains, “The pancaratrika-vidhim made things very simplified. The vedic-vidhi is not possible at the present age. Vedic-vidhi means one must be begotten by a brahmana, and he must have followed the family tradition. Then according to Vedic rites, he can be initiated or offered the sacred thread (upavita). But the pancaratrika-vidhi is especially meant for this age.
“Anyone who has a slight tendency to become a devotee should be given a chance. That is Lord Caitanya's special benediction. For example, Haridasa Thakura was born in a Mohammedan family, yet Lord Caitanya made him the namacarya, the authority of chanting Hare Krishna.” (SPT 27/12/69)
The pancaratrika-marga, like the vedic-marga, is also an ancient path of self-discovery existing since time immemorial. In the beginning of creation Lord Brahma heard the Vedas from Sri Krishna. At that time the demons Madhu and Kaitabha appeared from Maha-Visnu, entered Lord Brahma's mind and stole the Vedas. Krishna then manifested the Hayagriva incarnation to kill Madhu and Kaitabha. Lord Brahma asked Krishna to teach him the Vedas again, but just the essence since he might die at any moment.
For five (panca) consecutive nights (ratri) Krishna taught Lord Brahma the essence of the Vedas. That knowledge became known as the pancaratric knowledge, a system of practical philosophy and procedures for worship. There are hundreds of Pancaratras.
The Narada Pancaratra, for example, was spoken by Lord Siva to Narada Muni and later compiled by Vyasadeva. Srila Sanatana Gosvami's Hari-bhakti-vilasa contains the essence of this pancaratric knowledge.
Following the pancaratrika-marga, which includes Deity worship and chanting Gayatri mantras, keeps one off the material plane and fixed on the spiritual platform until love of God is awakened through the process of chanting the holy names of Krishna (nama-sankirtana). Perfection is achieved on the pancaratrika-marga when a disciple, by the mercy of the guru, attains svarupa-siddhi (realization of one's eternal spiritual identity).
At this time, one fully understands that the Deity is the Supreme Personality of Godhead, Sri Krishna, and he worships the Supreme Personality of Godhead through serving His devotees.
The vedic-marga incorporates the Vedanta, the philosophy based on the Upanisads. The essence of Vedanta is the Srimad Bhagavatam, a completely pure, transcendental work. The Srimad Bhagavatam depicts the way of worship and activities performed by those desiring to attain Bhagavan Sri Krishna through the path of bhakti and nama-sankirtana.
The pancaratrika-marga (which includes chanting Gayatri and doing puja) regulates and purifies the conditioned soul of his material tendencies, fixes him on the transcendental plane and maintains his fitness for serving the Lord. It also helps him to perfect his chanting of Hare Krishna and progress steadily on the path of perfection.
Excerpt from book Gayatri Mahima Madhuri by Mahanidhi Swami