The Bhagavad Gita (13.7) extols forbearance (kshanti) as a sign of knowledge. Vedanta considers forbearance (titiksha) as one of the six treasures necessary for a spiritual seeker. (Vivekachudamani, 19)
Sri Shankaracharya defines forbearance as "the bearing of all difficulties, miseries, and problems, without caring to redress them or worrying or lamenting on their account." (Vivekachudamani, 24) No doubt this definition is very idealistic, but it is important to strive to live up to the ideal, rather than lowering the ideal to our level. Says Swami Vivekananda, "One of the most insinuating things comes to us in the shape of persons who apologize for our mistakes and teach us how to make special excuses for all our foolish wants and foolish desires; and we think that their ideal is the only ideal we need have. But it is not so. The Vedanta teaches no such thing. The actual should be reconciled to the ideal; the present life should be made to coincide with life eternal."
Sri Ramakrishna taught, "The quality of forbearance is of the highest importance to every man. He alone is not destroyed who possesses this quality." Holy Mother Sri Sarada Devi says, "Forbearance is a great virtue; there is no other like it." Not impulsive reaction but only forbearance will help us lead a saner and meaningful life. Every impulsive reaction results in loss of mental energy, which in turn affects our physical health. Vedanta offers a deeper reason to practice forbearance: We are essentially divine, but this divinity is hidden in us. This divine Self is called the Atman, whose nature is infinite existence, infinite knowledge, and infinite bliss. Ignorant of this fact, we identify with our body and mind, and believe erroneously that we are limited beings. We look for lasting fulfillment and unalloyed happiness in the outside world, and become disillusioned in the long run. As we gradually free ourselves from the hold of our body and mind by spiritual practice, we get glimpses of our true nature. Our hidden divinity now begins to manifest in our thoughts and actions. On the other hand, rash and impulsive reaction makes us slaves of our body and mind, and we remain ignorant of the supreme fulfillment arising from Self-knowledge. Forbearance helps us gain true perspective of ourselves, purifies our mind, strengthens our will, and paves the way for a fruitful spiritual struggle.
Commenting on verse 13.7 of the Bhagavad Gita, Sant Jnaneshvar describes the characteristics of a person who is growing in forbearance: (1) He faces all good and bad situations in the same gracious manner with which one would wear ornaments of one's choice. (2) He does not feel bad when harassed by the threefold affliction (arising from one's body and mind, other beings, and natural causes). (3) He is equally happy on getting desirable or undesirable objects. (4) He bears with composure and equanimity pairs of opposites like heat and cold, honor and dishonor, pleasure and pain, and praise and blame. He is not self-conscious about his even-mindedness, since it has become second nature to him. He looks upon all that happens to him as part of himself and so does not feel that he is doing anything extraordinary in putting up with them. (5) He has no fear when facing any situation.