Barnes New Testament Notes

Verse 15. Jesus I know. His power to cast out devils I know. Comp. Mt 8:29.

Paul I know. Paul's power to cast out devils, Ac 19:12.

But who are ye? What power have you over evil spirits? By what right do you attempt to expel them? The meaning is, "You belong neither to Jesus nor Paul; you are not of their party; and you have no right or authority to attempt to work miracles in the name of either."