In his Gospel St. Mark (6:12-13) gives us an indication of this sacrament of the sick when he tells us that the apostles, going forth, "preached that men should repent, and they cast out many devils, and anointed with oil many sick people, and healed them."
However, the classical description which the Bible gives of the sacrament of Anointing of the Sick is found in the Epistle of St. James:
Is any one among you sick? Let him bring in the presbyters [priests] 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 man, and the Lord will raise him up, and if he be in sins, they shall be forgiven him.