πιστός

trusty, faithful, of persons who show themselves faithful in the transaction of business, the execution of commands, or the discharge of official duties, one who kept his plighted faith, worthy of trust, that can be relied on, easily persuaded, believing, confiding, trusting, in the NT one who trusts in God's promises, one who is convinced that Jesus has been raised from the dead, one who has become convinced that Jesus is the Messiah and author of salvation