The Teachings of Bhagavadgita :
Spiritual life is the greatest of adventures. In that way we can compare it to a battle. It involves careful preparation, as in a war. And, when you engage yourself in a war you do not go there merely to get defeated and thrown out; the intention is to win victory. So the practice of yoga, which is the greatest project that a person can embark upon in life, is in a way comparable to a battle or an encounter, for the purpose of which one has to make an almost infinite set of preparations – for days and months and years perhaps – as a culmination of one's existence here, as the fruit of the tree of one's whole life in this world. Hence, great care and caution has to be exercised. In a hurry, in a bustle and in a state of emotional enthusiasm, we are not supposed to enter into this field called 'life spiritual'. It is not an entering into a new way of life; rather it is an embracing of all life together in your own life. You are not going to live an isolated, queer type of cave life psychologically, but you are going to broaden your outlook and your vision of things, so that all life is included in your own life and your life becomes commensurate with every other kind of living.
You have heard that yoga is a union with something. It is a union no doubt, but with what? There are endless answers to this question. With what are you going to unite yourself in that you call yoga? The difficulty in answering this question arises due to a misrepresentation of facts by our senses, which indoctrinate us into the belief that we are independent contents of this world – each person is independent and perhaps one has nothing to do with the other, finally. I have touched upon this theme to some extent yesterday. But the truth is that you are not so independent as you imagine yourself to be. You have a freedom which is constrained by the operation of a universal law. A kind of violation of this universal principle is perpetrated every day in our life when we cling to things as externals, either in love or in hatred. Whether you like a thing or dislike a thing, your attitude towards the thing is almost identical from the point of view of pure psychology. Like and dislike are two aspects of a single attitude which is totally erroneous. Life is a continuity and is not constituted of bits or shreds, with no connection with one another. It is impossible to define life, because it is itself a definition of itself. There are certain things which cannot be defined in words other than the ones we use to designate them or indicate them – 'life', 'consciousness', even 'mind' are indefinable peculiarities.