This refers to a sincere renunciation of unwholesome actions. In other words, in the course of the meditation, unwholesome actions are transcended. The third power that issues from this practice is the 'power of habitual antidote,' or the power of persistent correction, which refers to the sincere resolve not to repeat the unwholesome actions one has done in the past. This is the power to refrain from doing unwholesome actions again in the future. This refers to the fact that, insofar as unwholesome actions belong to the level of conditioned reality, they do not really penetrate to the core of one's own being, which is the Buddha mind, or the nature of emptiness.
Unwholesome actions are, in reality, adventitious.
They are like the dirt that soils a white cloth, or the smoke or cloud that obscures the sky. Because of this, meditation on Vajrasattva results in the power of restoration, which is the realization of our intrinsic purity. The third preliminary is called preceptor yoga. The term yoga means 'yoking together,' connecting or identifying. The purpose of preceptor yoga is to establish a close bond between disciple and master.