Sri Sri Ravi Shankar:
Tapa helps to purify all the organs of the body and rid them of impurities. The entire body gets cleansed and all the sense organs become stronger with tapa.
Tapasya is not done to please God, or to attain self realization, but it is done to make the body and mind stronger.
You must have seen that so many saints do very austere penances (tapasya), especially among the Jains. The Jain saints are able to walk bare foot for long distances. 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. So this is one of the benefits of doing tapasya.
But you should not stretch or overdo this at all. Doing too much tapasya and troubling your own body is not advisable at all. It is wrong to do that.
There are some people who sit with four fires burning all around them, and one on top of their head and do meditation. It is called Panchagni tapasya. All this is not necessary. Torturing the body like this is wrong and should not be done. But a little bit of tapasya is necessary.
It is said, ‘Tapovai dwandva sahanam’, which means forbearing the opposites is tapasya.
Suppose you are travelling somewhere in a bus, and it is a 12 hour long journey for which you have to sit. Then that also is a sort of tapasya.
Being in a state of equanimity, and enduring whatever come, whether it is hot or cold, good or bad, praise or criticism, is tapasya.
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 criticizes you, can you listen to it with the same smile and equanimity, 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.
If you can like something, can you be a witness to it and not be feverish about it, 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.