Holy sacrament (Prasād) is an offering or item (often a snack or sweet) that has been given by a spiritually evolved person or Saint who is above the spiritual level of 70%.
When a person receives Holy sacrament from a Saint, he receives the Divine energy from that offering. The Divine or positive energy spreads throughout the body as shown in this drawing based on subtle-knowledge.
As the Divine energy received through the Holy sacrament is short lasting, a sure way of receiving constant Divine energy is through regular spiritual practice as per the 6 basic principles and chanting the name of God as per the religion of our birth.