Luke 9:1-2:

Then he called his twelve disciples together, and gave them power and authority over all devils, and to cure diseases.
And he sent them to preach the kingdom of God, and to heal the sick.

See also:

Matthew 10:1
Notes on Matthew 10:1
Mark 3:14-15
Mark 6:7
According to YOUR FAITH Be It Done unto You!
YOU Can Do Miracles
Don’t Preach a D- Gospel
What Is the Difference Between Unbelief and Doubt?
Must We Fast and Pray to Make Certain Demons Leave?
Sickness Is the Power of the Devil
Objection: As Many Doctors Can Tell You, Many People Make Themselves Sick – It Has Nothing to Do with the Devil
Objection: Mark 16:9-20 Was Not in Some Early Manuscripts
Condition: Demon Possession
Condition: Anything Else Not Listed Here