Vajrasattva practices are common to all schools of Tibetan Buddhism and are used both to purify obscurations so that the Vajrayana student can progress beyond preliminaries practices to the various yogic practices of tantra and also to purify any broken tantric vows after empowerment. As such, Vajrasattva practice is an essential element of Tibetan Buddhist practice. In addition to personal practice, the Vajrasattva mantra is regarded as having the ability to purify karma, bring peace, and cause enlightened activity in general.
In the Kalachakra Path, Vajrasattva Yab-Yum is inseparable from the nature body of the Buddha, the Primordial Buddha. It is this very ground of purity which makes the purification practices possible.