the obligation of loyalty or fidelity to a person, promise, engagement, etc.: Failure to appear would be breaking faith.
7.
the observance of this obligation; fidelity to one's promise, oath, allegiance, etc.: He was the only one who proved his faith during our recent troubles.
8.
Christian Theology. the trust in God and in His promises as made through Christ and the Scriptures by which humans are justified or saved.
Origin: 1200–50; Middle English feith < Anglo-French fed,Old French feid, feit < Latin fidem, accusative of fidēs trust, akin to fīdere to trust. See confide
mid-13c., "duty of fulfilling one's trust," from O.Fr. feid, from L. fides "trust, belief," from root of fidere "to trust," from PIE base *bhidh-/*bhoidh- (cf. Gk. pistis; see bid). For sense evolution, see belief. Theological sense is from late
14c.; religions called faiths since c.1300. Old Faithful geyser named 1870 by explorer Gen. H.D. Washburn, Surveyor-General of the Montana Territory, in reference to the regularity of its outbursts.