XV. Although we acknowledge the necessity of good works against the Epicureans, we do not on this account confound the law and the gospel and interfere with gratuitous justification by faith alone. Good works are required not for living according to the law, but because we live by the gospel; not as the causes on account of which life is given to us, but as effects which testify that life has been given to us.
Francis Turretin, Institutes of Elenctic Theology, trans. George Musgrave Giger, vol. 2 (Phillipsburg, NJ: P&R Publishing, 1992–97), 705. (17.3.15)