Turretin: Faith Is Not True Because It Perseveres

XII. Faith is not true because it perseveres, but it perseveres because it is true. Thus perseverance is not the cause of the verity of faith, but the consequent and the effect—for because it has solidity and a deep root in the heart, on this account it is constant and perpetually endures. As from lightness arises liability to fall, so from solidity arises stability. For although duration does not properly constitute the essence of a thing, still it so follows it that from it a judgment can well be formed concerning the truth of a thing a posteriori. Duration is an index of truth, as truth is the principle of duration.

Francis Turretin, Institutes of Elenctic Theology, ed. James T. Dennison Jr., trans. George Musgrave Giger, vol. 2 (Phillipsburg, NJ: P&R Publishing, 1992–97), 15.15.12 (p. 592).