Penance means voluntary disclosure acceptance of responsibility for the misdeeds committed by oneself. In due course all misdeeds including the recent ones, create layers of a thick envelope which form a miserable cocoon around the soul and becomes engrained as evil instincts or regressive traits (Ku Sanskar) create obstacles in the efforts of sell advacement.
It is only when the reasons and causes behind the occurence of the misdeeds are pondered, understood and confessed to yourself, a guru and finally the lord, that you can be considered worthy and deserving of being purged of the guilt of misdeeds, This ensures that corrective measures are taken in future situations so that further misdeeds are not committed.
It takes confidence will and inner strength to take up penance and intense sadhana in the correct spirit. In order to remove regressive traits and eradicates the burden of guilt which stands as an obstacle to all progress, one should willfully take up the process of meditation, self study and partake in the company of spiritual teachers (Satsung), undergo fasting, chanting mantras repetetively and give spiritual treatment to oneself. This is true Penance.