Pistis is the New Testament's signature theological term, appearing 243 times to name the essential human response to God's action in Christ. In its overwhelming primary sense, it denotes the active disposition of trust and belief — from the faith that heals ('Your faith has saved you,' Matt 9:22) to the faith that justifies (Rom 3:28, Gal 2:16) to the faith contended for as apostolic deposit (Jude 3). Yet in a handful of passages, pistis shifts to an objective quality: faithfulness as a fruit of the Spirit (Gal 5:22) or God's own reliability (Rom 3:3). German 'Glaube' covers both senses, while Spanish distinguishes 'fe' (faith) from 'fidelidad' (faithfulness) — a lexical split that illuminates the word's dual nature.