Faith is Faithfulness to our relationship to God

If one thinks that "belief" is what God wants from us, then doubt and disbelief are experienced as sinful.

Faith is faithfulness to our relationship to God.  It means what faithfulness does ina  committed human relationship...Faith as fidelitas does not mean faithfulness to statements about God, whether bibilical, credal, or doctrinal.  Rather, it means faithfulness to the God to whom the bible and creeds and doctrines point.  Fidelitas refers to a radical centering in God

...when the prophets indict Israel as adulterous or Jesus speaks of "and evil and adulterous generation" they are not saying that there is a lot of wife swapping going on.  Rather, they are referring to unfaithfulness to God and God's covenant.

Marcus Borg, The Heart of Christianity, pgs. 30, 32-33