The oil of gladness with which Christ was anointed was a spiritual oil; it was in fact the Holy Spirit himself, who is called the oil of gladness because he is the source of spiritual joy. But we too have been anointed with oil, and by this anointing we have entered into fellowship with Christ and have received a share in his life… While symbolically, on our foreheads and senses, our bodies are anointed with this oil that we see, our souls are sanctified by the holy and life-giving Spirit.
–Saint Cyril of Jerusalem (c. 313-386)
About
