The function of the yoga is to train the body and the mind. If a wage earner applies the principles of the Gita to his life he will become a better wage earner. A farmer will equip himself better if he only translates the Gita principles into action. A merchant is bound to thrive in his business by putting these tenets to practice. An officer will execute his duty more efficiently when he becomes a yogi.
Man becomes well equipped for life by taking to yoga.
An efficient man is otherwise called a yogi. While playing the part of the charioteer, Sri Krishna is controlling the reins of the four white horses yoked to the chariot. They are like the four yogas yoked to the human frame. The human body is the chariot. This body chariot is driven by the Supreme Lord.