Basis of Yoga -

"Work incessantly, but give up all attachment to work." Do not identify yourself with anything. Hold your mind free. All this that you see, the pains and the miseries, are but the necessary conditions of this world; poverty and wealth and happiness are but momentary; they do not belong to our real nature at all. Our nature is far beyond misery and happiness, beyond every object of the senses, beyond the imagination; and yet we must go on working all the time. "Misery comes through attachment, not through work." As soon as we identify ourselves with the work we do, we feel miserable; but if we do not identify ourselves with it, we do not feel that misery. If a beautiful picture belonging to another is burnt, a man does not generally become miserable; but when his own picture is burnt, how miserable he feels! Why? Both were beautiful pictures, perhaps copies of the same original; but in one case very much more misery is felt than in the other. It is because in one case he identifies himself with the picture, and not in the other. This "I and mine" causes the whole misery. With the sense of possession comes selfishness, and selfishness brings on misery. Every act of selfishness or thought of selfishness makes us attached to something, and immediately we are made slaves. Each wave in the Chitta that says "I and mine" immediately puts a chain round us and makes us slaves; and the more we say "I and mine", the more slavery grows, the more misery increases. Therefore Karma-Yoga tells us to enjoy the beauty of all the pictures in the world, but not to identify ourselves with any of them. Never say "mine". Whenever we say a thing is "mine", misery will immediately come. Do not even say "my child" in your mind. Possess the child, but do not say "mine". If you do, then will come the misery. Do not say “my house," do not say "my body". The whole difficulty is there. The body is neither yours, nor mine, nor anybody's. These bodies are coming and going by the laws of nature, but we are free, standing as witness. This body is no more free than a picture or a wall. Why should we be attached so much to a body? If somebody paints a picture, he does it and passes on. Do not project that tentacle of selfishness, "I must possess it". As soon as that is projected, misery will begin.

So Karma-Yoga says, first destroy the tendency to project this tentacle of selfishness, and when you have the power of checking it, hold it in and do not allow the mind to get into the ways of selfishness. Then you may go out into the world and work as much as you can. Mix everywhere, go where you please; you will never be contaminated with evil. There is the lotus leaf in the water; the water cannot touch and adhere to it; so will you be in the world. This is called "Vairâgya", dispassion or non-attachment. I believe I have told you that without non-attachment there cannot be any kind of Yoga. Non-attachment is the basis of all the Yogas-

Swami Vivekananda