Sometimes, what a voluminous book cannot explain can be explained in a single sentence! It is true about yoga. Yoga is not a mere word; it is a vast subject with many dimensions.
The wise saying goes, Yoga karmasu kaushalam!-which means, Efficiency in work is yoga!
What you do is not important. How you do what you do, is important!
Yoga also means union. What union? Whether union between the body and the mind? Or the mind with the spirit? The traditionally accepted belief (or truth, depending upon the level of your spiritual progression) is the union between the Jeevatman and the Paramatman between ones individual consciousness and the universal consciousness.
Yoga is a very vast subject. Attempting even an introduction in a small articles is an impossibility. Nevertheless, some important observations need to be understood when you speak of yoga.
Yoga has got something to do with the health of your physical body.
Yoga has got something to do with your mental health.
Yoga has something to do with your intellectual health.
Yoga has got everything to do with your spiritual being.
The ultimate stage can only be realized. No amount of assertions, explanations, and arguments and counter arguments can take you up there. The domain of silence can only be achieved through silence!
Yoga is intensely linked to breathing. It is about channeling the energy through breath. Another intimate alley of yoga is meditation. You can not think of yoga without understanding at least some of the basic techniques of meditation! Spiritual appreciation as to the nature of the human body, who controls it all of the time, is absolutely essential for proper understanding of various practices that make the science of yoga.
A word about Karma Yoga. The fundamental principle Karma Yoga is, Do your duty and do not ask for the reward. What youngster of the modern generation would accept this principle? If I do my duty, I must get the reward! Arent there people who dont do any work and still get the reward.
The word yoga makes its entry at this level of thinking of an individual. The correct interpretation of this principle of yoga is that do your duty but dont ask for the reward You will get the right reward, at the right moment!
Every action has a reaction and the intensity of the reaction is in proportion to the intensity of the action. Over this the scientists and the spiritualists agree! One of the rare agreements between the two contending forces. Normally opposing forces! If you agree on this, dont you think that it is necessary for you to agree that your every action, good or bad, will be rewarded as per the proportion it deserves?