Oil is a symbol of anointing - not totally necessary but in the scriptures so we should probably do it. Prayer is the request for healing. Prayer is the way we petition, as opposed to sacrifices or spiritual exercises, or forms of denial. God is merciful in this regard. We have to have faith, we can't be testy or put God on the block. You have to all in for this one. Confession is most often overlooked, but confession is key. Our sins get in the way of spiritual life, so confession, and change, is central