Tapas (Sanskrit – heat) first appears in the Rig Veda as brooding heat. The hen invests her time and energy in keeping the eggs warm and they hatch, releasing new life. Heat is associated with birth and transformation and appears on every level of experience to the Vedic poets. From the heat of passion or sexual heat, the increasing heat of the sun that brings spring after winter, to the courage heat of the soldier who fights to protect the people, good things come from Tapas.
Some of the earliest references of Tapas are found in the Ŗg Veda (10.154.5), Satapatha Brahmana (5.3-17), and Atharva Veda (4.34.1, 6.61.1, 11.1.26) where Tapas is described as the process that led to the spiritual birth of Rishis – sages or seers. The Atharva Veda suggests all the gods were Tapas-born (tapojās), and all earthly life was created from the sun’s Tapas. In the Jāiminiya-Upanisad Brāhmaņa, life perpetuates itself and creates progeny by Tapas, a process that starts with sexual heat.
In the Upanishads, the fruit of Tapas was considered wisdom, the wisdom that separates Brahman from Maya. The binding force of Maya was seen to pull the soul (Brahman/Atman) to sense objects through the senses. Tapas became the practice of holding on to essence and denying the sense pull that draws one into ignorance (Maya). In the fervor to become free of the senses, Tapas became the harsh austerities we see in early Jaina, Buddhist and Hindu monastic orders.
The Bhagavad Gita is ambivalent regarding Tapas. Austerities that hurt the body are prohibited strongly. Instead, relatively mild practices are given, and Tapas is divided into three levels of practice: speech, mind and body (Bhagavad Gita chapter 17).
Later on in the Puranas and epics, Tapas becomes a powerful transformational tool with many stories of yogis who, through profound Tapas, reached enlightenment.
Tapas was seen as a kind of spiritual currency that could be cashed in for spiritual favors. Many yogis, and some demons, performed intense Tapas that created a disturbance in the universe. When the disturbance became great enough, a god appeared and offered the practitioner a boon. The practitioner took the boon and abandoned the Tapas, allowing the universe to return to normal.
In Patanjali’s 8-fold path, Tapas is reduced to the level of a Niyama.
Through ascesis or training of the senses (Tapas), there comes a destruction of mental impurities, and an ensuing mastery or perfection over the body and the mental organs of senses and actions (indriyas). YS 2.43
We can interpret this as meaning that Tapas generates discipline; lack of control is an impurity or Klesha of the mind. The disciplined mind can stop the chitta vrittis, the very purpose of yoga. Tapas is not doing those things that are contrary to yoga.
Swami Kripalu and Tapas
Swami Kripalu used the word Tapas to refer to all spiritual practices and efforts to grow spiritually or to bring positive change. To him, Tapas was going against our natural or habitual behaviors and manifesting more spiritual or Sattvic behaviors.
When speaking of his own Tapas, Swami Kripalu referred specifically to his meditation to reach enlightenment. He was often apologetic and humble, attributing his progress to god’s grace. When teaching about Tapas, he often referred to the Bhagavad Gita and used its model of Tapas as disciplining speech, mind, and body.
To speak the truth is the sadhana of your speech. It is the penance of your speech.
“Tapa” means to heat. Just as cold air is purified by heat, so also, speech is purified by the truth. That is why it is called “Tapas.” Language and speech are purified by self-control. All self-control is called “Tapas.” That self-control is itself called fire.
Swami Kripalu encouraged his students to do Tapas at their own level. He coached and encouraged but was rarely condescending or judgmental.
Tapas is one of the five niyamas. The word ‘Tapas’ is so profound that to talk about it in front of average person is almost like an insult. And yet the average person in the society can accept a portion of it according to his own capacity. Without Tapas or austerity, the life cannot be properly molded.
In speaking of his own Tapas and in his instruction to his students, Swami Kripalu often used religious or devotional language. He taught that we should love god and let the intensity of our Tapas be a reflection of our devotion.
This light is the light of knowledge divine, it is the light of love and it is the light of austerity. One who holds this divine light, they also have Gurudev in their hearts and they also have Govindaji, the Lord, in their hearts, too. But you have to become that light, and continuously burn, continuously remain lit. This burning itself is the sadhana. That is the Tapas.
All quotes above by Swami Kripalu are from his discourses and informal talks. Edited versions may be available in the Prem Yatras and A Sunrise of Joy: The Lost Darshans of Swami Kripalu, by John Mundhal.