Being in a state of equanimity, and enduring whatever comes — hot or cold, good or bad, praise or criticism — is tapasya (penance). Can you listen to an insult with the same equanimity as when you listen to compliments? That is tapasya. when someone praises you, you listen to it with a smile. when someone criticises you, can you listen to it with the same smile and watch what is happening inside you? That is tapasya. When you do not like something but are able to undergo that, then that is tapasya. Forbearing the opposites is called tapasya, and it is essential in life. The extent to which we follow tapasya in life, to that extent we become stronger and stable.
Tapasya is not done to please God or to attain self-realisation, but to make body and mind stronger. Tapa helps purify all the organs of the body and rid them from impurities.
You must have seen many saints do very austere penances. They do not feel very cold in the winters, or too hot during the summers. They develop a resistance towards extreme climatic conditions because of their tapasya. But not stretch or overdo this.Doing too much tapasya and troubling your own body is not advisable.
There are some people who sit with four fires burning all around them, and one on top of their head and then meditate. This is called panchagni tapasya. All this is not necessary. Torturing the body like this is wrong and should not be done.
A little bit of tapasya is necessary. It is said “Tapovai Dwandva Sahanam”, which means bearing the opposites is tapasya. Suppose you are traveling somewhere in bus, and you have the journey is 12 hours long. That, too, is a type of tapasya.
– Sri Sri Ravi Shankar