Mark 6:12-13:

And they went out, and preached that men should repent.
And they cast out many devils, and anointed with oil many that were sick, and healed them.

Notes on Mark 6:12-13:

Jesus preached repentance.  The disciples preached repentance.  Jesus said to proclaim repentance and forgiveness of sins in His name everywhere (Luke 24:45-47).  So the idea that repentance should not be preached anymore certainly didn’t come from Scripture.  The preaching of repentance may not be popular today, but Jesus did not command you to be popular.

This passage mentions anointing with oil, while other passages about the ministry of the disciples make no mention of oil.  Jesus said that we would lay hands on the sick (Mark 16:18) without oil being a requirement.  Oil is required if the sick person has called for the elders of the church to pray over him (James 5:14-15).

See also:

YOU Can Do Miracles
Should We Anoint the Sick with Oil When We Lay Hands on Them?
Condition: Demon Possession
Condition: Anything Else Not Listed Here