To be sure of reaching our destination when we undertake a long journey, we must get rid of anything that can create obstacles.
On the Buddhist path, that corresponds to the stage called “purification”.
Purification does not mean washing some kind of original impurity out of our human nature. If our nature was inherently bad, it would be useless to try to make it pure, just as we cannot make a piece of coal white by washing it, even for centuries.
Rather, we purify, or remove, the obscurations that veil our true nature or what we might call our “original goodness.” This purification is like extracting gold from its ore: the impurities are removed to reveal its brilliance and natural perfection.
Or, it can be compared to the wind driving away the clouds that hide the sun: the sun’s light remains unchanged. It was already bright even when hidden.
Buddhism distinguishes two types of obscuration that must be eliminated by this process: the obscuration of disturbing emotions such as desire, hatred, ignorance, pride, and jealousy, and the more subtle conceptual obscuration, which prevents us from seeing the ultimate nature of things.
Source: Taken from Ricard, Matthieu. On the Path to Enlightenment: Heart Advice from the Great Tibetan Masters. Shambhala. Kindle Edition.
It is important to purify negative karma and emotional afflictions. This is achieved in part through Vajrasattva Practice.
In order to make the Vajrasattva purification effective, it is essential to employ all the four powers in the purification. They are:
(1) The power of support, Vajrasattva as the spiritual force to rely on for the purification.
(2) The power of remorse, feeling strong remorse for the misdeeds we have committed, which are comparable to our having consumed poison.
(3) The power of commitment, a strong promise not to repeat the misdeeds again.
(4) The power of antidote, the formula of Vajrasattva meditation as the means of purification.
Source: Thondup, Tulku. Enlightened Journey: Buddhist Practice as Daily Life. Shambhala. Kindle Edition.
The four powers could be termed as (1) refuge; (2) regret; (3) repentance; and (4) remedy.