Having made pleasure and pain, gain and loss, victory and defeat the same, engage yourself in battle for the sake of battle; thus you shall not incur sin.

—Bhagavad Gita 2.38

Pleasure and pain are not real. These are just notions of the mind. Without this realization the mind is always busy running after something that it thinks would be pleasurable or running away from things it finds painful. With the mind running here and there we won’t be able to perform any meaningful work. Besides, our understanding gets clouded, we lose our priorities and all immoral acts proceed from the ignorance of the fact that pleasure and pain exist only in the mind, not in the thing outside.

So when you rise above pleasure and pain, you won’t do anything inappropriate or sinful. There is no question of acting out of selfishness. No harming someone else just for the sake of gaining pleasure or losing pain because you know pleasure and pain don’t exist outside. When selfishness gets out of the way, all work you do would be for the greater good of the world. And the mind remains calm, there is no pleasure to run after, there is no pain to run away from, the mind is always focused on the work on hand. A calm and focused mind just does what needs to be done irrespective of chances of success or failure. Such a mind that works for work’s sake always turns out high quality work.

But can this level-headed-ness in success and failure be practical? Well, we should just try as much as we can, try for trial’s sake! If you want a practical example you should get to know MS Dhoni, who has this ‘ability to remain level-headed, at the height of success or depths of failure’. MSD is the current captain of the Indian cricket team and one of the most successful captains in Indian cricket.

In this world, whatever is gained is gained by only by self-effort; where failure is encountered, it is seen that there has been slackness in the effort. This is obvious, but what is called fate is fictitious, and is not seen. …

Self-effort is of two categories: that of past births and that of this birth. The latter effectively counteracts the former. Fate is none other than self-effort of a past incarnation. There is constant conflict between these two in this incarnation and that which is more powerful triumphs.

Self-effort which is not in accord with the scriptures is motivated by delusion. When there is obstruction in the fruition of self-effort one should examine it to see if there is such deluded action, and if there is it should be immediately corrected. There is no power greater than right action in the present. Hence, one should take recourse to self-effort, grinding one’s teeth, and one should overcome evil by good and fate by present effort.

…

… What is called fate or divine will is nothing other than the action or self-effort of the past. The present is infinitely more potent than the past. They are indeed fools who are satisfied with the fruits of their past effort (which they regard as divine will) and do not engage themselves in self-effort now.

— Yoga Vasishtha (tr. by Swami Venkatesananda)