Today in chapter 5 of the Letter to James it says,
Is anyone among you sick? He should summon the presbyters of the Church, and they should pray over him and anoint him with oil in the name of the Lord. The prayer of faith will save the sick person, and the Lord will raise him up. If he has committed any sins, he will be forgiven.
Notice that it doesn't say "gather a group of Christians, have them stand around the person in a circle, and put a hand on them, prayer over them, and have someone anoint them"
St. James is very specific the person must be a presbyter (English translation: priest). We are still officially ordained "presbyters". The group of priests collectively is called the Presbyterate.
Praying for one another is certainly important thing to do, but it does not take the place of the sacrament, the anointing according to the direct instructions of the word of God.
Why does it have to be a presbyter? Many Catholics will ask, why can't deacons annoit. Firstly, because the Bible is specific. Secondly, the reason St. James is so specific is that the Sacrament of Annoiting is not simply about physically healing. Notice the last part,
If he has committed any sins, he will be forgiven.
The Bible has always known what medicine is just beginning to admit, that the human person is one. You cannot divide them up and deal with the physical, the psychological, and the spiritual separately. All of the dimensions are interconnected.
The Annoiting of the Sick always brings healing on the level that the person most needs it, from God's point of view. Sometimes that healing is the ultimate healing, passage into eternal life. No sacrament is ever without effect.
Today we thank God for the gift of this sacrament, and when we are seriously ill we should follow the instructions of St. James.