Holy Unction (the Anointing of the Sick) is a Church Sacrament performed over a sick person by a council of priests (in an extreme case — by one priest), consisting in invoking upon the sick person, through prayers and anointing with consecrated oil, the healing and cleansing grace that heals infirmities of body and soul.
Bible quotes:
“Is anyone among you sick? Let him call for the elders of the church, and let them pray over him, anointing him with oil in the name of the Lord. And the prayer of faith will save the sick, and the Lord will raise him up. And if he has committed sins, he will be forgiven” (James. 5:14-15)
“So they went out and preached that people should repent. And they cast out many demons, and anointed with oil many who were sick, and healed them” (Mark. 6:12-13)
“And when He had called His twelve disciples to Him, He gave them power over unclean spirits, to cast them out, and to heal all kinds of sickness and all kinds of disease” (Matt. 10:1)
“Heal the sick, cleanse the lepers, raise the dead, cast out demons. Freely you have received, freely give” (Matt. 10:8)