“[A]n untruth, namely, that we are justified only by the passion of Christ. But if this were so, we should be justified without fulfilling the law. For (as I have said) we owe to God a double debt: one by creation, namely, the fulfilling of the law in all things from our first beginning; the second, since the fall of Adam, namely, a satisfaction for the breach of the law. Now the passion of Christ is a payment of the second debt, but not of the first; whereas both must be answered. For ‘cursed is he that doth not continue in all things written in the law, to do them.” (See Gal. 3:10) The passion of Christ procures deliverance from hell, but alone by itself considered, it does not purchase a right to eternal life.”
William Perkins, Commentary on Galatians in Works, 2:115 (HT: Inwoo Lee)