Romans 13:4; Romans 15:8; Romans 16:1

4 for it is a minister of God to you for good. But if you do what is evil, be afraid; for it does not bear the sword for nothing; for it is a minister of God, an avenger who brings wrath on the one who practices evil.
8 For I say that Christ has become a servant to the circumcision on behalf of the truth of God to confirm the promises given to the fathers,
1 I commend to you our sister Phoebe, who is a servant of the church which is at Cenchrea;