'Faithful' in the Bible

To the saints and faithful believers in Christ [who are] at Colossae: Grace to you and peace [inner calm and spiritual well-being] from God our Father.

You learned it from [our representative] Epaphras, our beloved fellow bond-servant, who is a faithful minister of Christ on our behalf

As to all my affairs, Tychicus, who is a much-loved brother and faithful assistant and fellow bond-servant in the Lord, will give you all the information.

and with him is Onesimus, our faithful and beloved brother, who is one of you. They will let you know everything about the situation here [in Rome].