“By the sacred anointing of the sick and the prayer of the priests the whole Church commends those who are ill to the suffering and glorified Lord, that he may raise them up and save them. And indeed she exhorts them to contribute to the good of the People of God by freely uniting themselves to the Passion and death of Christ.”
–Catechism of the Catholic Church, 1499, quoting Lumen Gentium, 11
All of the Sacraments use symbols to help us reflect on the action of God in our lives. Oil has been used since ancient times to heal. Think of the ointments used when one burns themselves. Oil has been used to bolster strength. Ancient Greek wrestlers poured it on their bodies before a competition. There is no wonder oil is used as we encounter God at the time of suffering and illness.
For more information about the Anointing of the Sick, call your parish or talk with the spiritual care ministry at a hospital, nursing home or other facility of residential healthcare.