In traditional religion the understanding of God, Buddha, or an absolute being is always related to this world. In other words, God appears in the form that we can understand. For example, God appears as Buddha, Kanzeon Bosatsu, or, in Christianity, as Jesus Christ, and, in Shintoism, as the god Amaterasu Omikami (sun), to protect peace on earth. So, traditional religion, basically, centers, on this world, relates to this world and worships God or Buddha who saves this world.
The center of esoteric religion is not of this world. The center is God or Buddha, not this world (us). The main purpose of esoteric religion is to transcend being human and become Buddha, God. In other words, unite one with God. We have evolved this much (to human beings) but are still not completed. In other words, we are in the middle of our evolution. The practices taught by esoteric religion is for human beings to evolve to be above the human being. Tantra yoga is certainly an esoteric part of yoga. Generally speaking, you can consider that Hinayana, Mahayana, Jodo sect, Nichiren sects, etc., of Buddhism as traditional religions while Vajrayana, Shingon, Tendai sects, etc. as esoteric. Zen Buddhism? Zen Buddhism is part of Mahayana tradition so it is supposedly a traditional religion. But when you look deeper into its teaching and practice, you'll understand that its practice is a supreme form of Tantrism. And in Christianity, Protestantism = traditional religion and the esoteric part of Catholicism is Tantrism. Generally speaking, yoga has various styles and you can separate them into two categories: classical yoga and Hatha (esoteric) yoga.
Traditional Religion/Classical Yoga
To control or destroy the three dimensional, wordly desire of human beings in order to make this world holy/sacred---this is known as classical yoga.
To use positive physical and spiritual practice, to reform consciousness rapidly, to make holy and sacred the third dimensional world view (outlook of the third dimensional world) to become one with God---this is known as Hatha Yoga. Therefore, Hatha Yoga is part of Tantrism, an esoteric religion.
So, classical religion = traditional religion, and Hatha Yoga is esoteric ( Tantra) yoga. Actually, Hatha Yoga is the root of Tibetan Buddhism, Taoism, Chineze Zen and Japanese Vajrayana (Shingon) Buddhism.
An important characteristic of Tantrism is the emphasis on actual practice and technique rather than philosophy. Therefore, a Guru (master of Tantric technique) becomes very important.
THREE BODIES OF HUMAN BEINGS
Tantra Yoga was founded by God, Lord Siva. According to Tantra, man is a totally "free being", almighty being. In the process of becoming God (evolution of mankind), we have three different dimensional bodies and minds. Step up one by one and realize and awaken the existence of a higher dimension of your body and mind and go to the land of God. Or be one with God or become God or return to God or enlightenment, self-realization or whatever you want to call it... finally, you'll be free from these bodies and minds... you are not body or mind, then who are you? ...I am not this body and I am not my astral body, I am not my mental body and I am not a mind. Then who am I??? You are eternal soul. You are spirit! Priests will tell you so (because the Bible said so...) Yes, we are eternal soul and spirit, there are many names for it. (Different religions have different names for it. Many names of one same thing. So don't fight over the different names). Body and mind is not you. You are the eternal soul. Opposite of eternal is temporal. So here unbalance occurs. Soul is eternal (beginningless, endless). Body is temporal. Our body lasts about 100 years, but the soul is eternal. Then where do you go after you die and lose your body? Unless you attain enlightenment (self-realization, to realize that you are an eternal being, realize that you are the God, realize who you really are), you will keep receiving new bodies, and this is called reincarnation.
THREE BODIES AND MINDS
- Physical body and its mind (mind that is related with material body).
- Astral body and its mind (emotional sense).
- Mental (causal) body and mind (intuition).
In these three bodies and minds, the physical body and mind exist and function in this phenomenal (material) world. In the surface area of Yo (Yang), while it is supported by the astral and mental body, In (Yin). The astral and mental body cannot be observed by the five physical senses and mind.
Physical Body (Material Body)
The soul (self) is beyond the physical body. The physical body is just a vehicle for you. The physical body is the place to experience happiness (good karma) and misery (bad karma) and is made up of five elements. You obtained this body as the result of your past karma. All the problems (or suffering) in life comes from ignorance (I am the body consciousness), in this way almost everybody is ignorant (I am the body consciousness).
Astral Body. This is your second vehicle.
The astral body is made up of life-force or prana energy (also known as "ki" in Japanese or "chi" in Chinese), senses and mind. The astral world is also known as the 4th dimension. The physical body functions in this material (physical) world, likewise we use our astral body for activities in the astral world. Dreams come from the astral dimension, and when you practice your meditation, you are stepping into the astral dimension.
Our senses and mind are in the astral dimension, and when people die senses and mind still exist. Everybody has an astral body (or rather, the astral body has every body).
Mental (Causal) Body.
This is your third body, or 1st body rather.
The mental body is the cause of astral and physical body. The causal body is the cause of the mistake of "I am the body" consciousness.
These three bodies and mind exist in different dimensions. But the three bodies make one complete human being. Like there is no tree without roots.
These three different dimensional bodies interrelate with chakras. Chakras function as a center of the three different bodies and it mediates prana (ki energy) from the different bodies. It converts the physical prana to astral energy or converts astral energy to physical energy to vitalize the body and mind. Therefore, activating and developing chakras will bring people into a higher level of consciousness and also be able to support the lower level of existence.