Paramatma has become as Jeevatma and in our two eyes is present in two states.
Uniting this two states or two divine lights of our eyes is what is Penance. Vallalar tells how one has to do penance as “Thinking & Thinking with Consciousness and with relaxed and calm mind and with full love and bathing with overflowing tears from the eyes”. Vallalar says this is the way of doing penance. Thinking of our eyes and thinking of the divine light in our eyes and with consciousness that is got in the eyes, with the mind fixed in the consciousness your mind will become calm and relaxed. When this calmness and relaxation increases, then compassion will blossom. Because of we fixing our mind on the divine light in the eye there will be increase in sensation in the eyes which result in tears overflowing. If we keep on continuing this penance as said, the divine light in our eyes will increase. Slowly it will spread throughout our body and will convert this physical destructible body to divine light body.
This is the noblest penance. The divine art of making Jeeva(soul) as Siva. Everyone in this world should learn this divine art. This is the only way for us our jeevatma which is of tiny divine light to reach the supreme infinite divine light which is paramatma the supreme lord.