In Vedās, a religious life is prescribed for all those who have :
a. Absence of Ātma Brahman Aikya jñanam.
b. Who have rāga-dveśa.
Absence of knowledge that the real nature of oneself- Ātma, is in fact, Brahman – the vast. Popularly referred to as Self-knowledge. The Self here is Ātma as oneself, and not the notion that I am an individual. This absence is referred to as Self-ignorance or simply ignorance. Ignorance is not referring to absence of any objective knowledge, like that of Physics, Economics etc. But it is stating the ignorance regarding Self-knowledge.
In the absence of Self -knowledge, the obvious outcome is “I am an individual”. And in such a notion of individuality, obvious is the presence of rāga-dveśa, likes and dislikes.
Man is afflicted by his Self ignorance primarily. It is the root cause of “ALL” the sorrows. Sprouting from it, man then gets afflicted by the likes-dislikes. In essence, the Vedās point out that a human being, irrespective of his gender, race, colour etc. spends away his life being constantly disturbed. Sorrow is encompassing all the felt disturbances.
But, an human being, again irrespective of his gender, race, colour etc. also has the equipped faculties, to gain this Self-knowledge. In the presence of which the root of Self -ignorance gets uprooted, there is then no locus for the individuality, and thus, no likes and dislikes get formed. The person of Self-knowledge, Such a human is referred to as “liberated”. Having fulfilled his human birth potential.
To uproot Self-ignorance, a lot of internal preparation is required. Just as to sow a seed, the soil is tilled; so too, for Self-knowledge, the human mind needs tilling.
This tilling is the job of a religious life.
Does every religion then take one to Self-knowledge?
No. Though ALL religions, when followed, cultivate the soil.
Vedic vision held the performance of the Vedic Karmas as religious. This was the karma-kanda, portion of Vedās detailing the knowledge regarding Karmas to be performed as per your notions of individuality. Abiding in the performance of the prescribed Karmās was being religious.
What was the advantage of this vision? The uniqueness of the vision of the Vedas? To the extent a person abided in his ordained karma, to that an extent indirectly his internal preparation took place. The source of sorrow coming from likes-dislikes got managed. And as one got prepared, the Vedās effortlessly revealed Ātma-jñana, through the Vedānta part, also called the Upanishads. Knowing which the final source of sorrow was destroyed. The one with Self-knowledge, now is the One. Where there is no sorrow. For sorrow to be, there has to be duality. But, for the Ātma-jñani, where is the other?
Thus, Vedic Karmās relevance as a religious life. And as with any knowledge, the chances of it being understood is relative, so too with Vedic knowledge. And the non-understanding leading to misunderstanding gets compounded when the knowledge is regarding the very Subject, the person, who has to re-know himself. This leads to layers and layers of deep-rooted superstitions, fanaticism, blind beliefs, rigid adherences, which more often destroy the very purpose of knowledge. And moreover, destroy the very potential of a human existence.