Mark 3:14-15:

And he ordained twelve, that they should be with him, and that he might send them forth to preach,
And to have power to heal sicknesses, and to cast out devils:

Notes on Mark 3:14-15:

In Mark 6:7, Jesus does something similar, though only demons are mentioned, and there is the added detail that He sent them out two by two.

See also:

Matthew 10:1
Notes on Matthew 10:1
Mark 6:7
Luke 9:1-2
Are Some Illnesses Harder to Be Healed Of Than Others?
Condition: Demon Possession
Condition: Anything Else Not Listed Here