'Faithful' in the Bible

Paul, an apostle of Jesus Christ by the will of God, to the saints which are at Ephesus, and to the faithful in Christ Jesus:

With right good will, be faithful to your duty as service rendered to the Lord and not to man.

But that ye also may know my affairs, and how I do, Tychicus, a beloved brother and faithful minister in the Lord, shall make known to you all things: