And [Jesus’s disciples] cast out many demons and anointed with oil many who were sick and healed them. (Mark 6:13)
Is anyone among you suffering? Let him pray. Is anyone cheerful? Let him sing Psalms. Is anyone among you sick? Let him call for the elders 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 one who is sick, and the Lord will raise him up. And if he has committed sins, he will be forgiven. (James 5:13-15)
In the old covenants, priests and kings were ordained through anointing with oil. In the new covenant, all God’s people are priests (1 Pet. 2:5) and are seated with Jesus as kings (Eph. 2:6). You might expect that anointing would be used for all believers as a sign of our union with Jesus the anointed one through his Holy Spirit. So it is a little startling that God appoints anointing, not for our baptism, but for those who are sick or in pain.
Of course there is no magic in either the oil or in the act of anointing. Instead, what this is showing us is that Christians who suffer sickness or pain have a unique privilege of closer fellowship with Jesus as they suffer under the curse. You could say that this anointing establishes a sort of office of suffering, in which Christians who endure sickness and pain are recognized and honored as having a special position in the service of our anointed king.
When the elders of the church anoint and pray for those who are sick, the church is, through her elders, honoring those whom Jesus has called to suffer, and praying that Jesus will by his Holy Spirit sanctify their suffering for his glory and praise. The church is also identifying sick believers with Jesus, the anointed one who heals us (Matt. 11:1-16), and with the Holy Spirit, the one who brings life to our mortal bodies (Romans 8:11). Finally, through this we pray earnestly that Jesus will bring their suffering to an end, just as Jesus’s own suffering was finally crowned with his glorification and reign.