The fourteen fundamental vows of the Mantrayana invoke the power of kaya, vaca, and citta, the body, speech, and mind of the Enlightened Ones.
They were considered far more binding than the vows a monk would take on receiving ordination. Since breaking these vows or discontinuing the practices might cause harm to the initiate and also to the teacher, it was vital that the initiate have a clear understanding of what was involved and a firm resolve to honor the commitments.
Otherwise, the power of the initiation would be lost and there could be very negative consequences.
Tarthang Tulku Rinpoche
Mind over Matter