The author presents a systematic exposition of Reformed Christian doctrine, following the larger catechism to explain union and communion with Christ, effectual calling, regeneration, justification, and justifying faith. He defines union with Christ as a spiritual, mystical yet real head-member relation, distinguishes the gospel offer from effectual calling, and defends regeneration as a supernatural work of the Spirit that precedes faith. The treatment of justification emphasizes imputation of Christ’s righteousness, the role of a surety, pardon as free grace, and that faith, not works, is the instrument of justification. Throughout, scriptural arguments are offered against Pelagian and Socinian positions and objections are anticipated and answered.