On this subject we call the “Word of God” (for we know well that the Eternal Son of God is also so named) the canonical books of the Old and New Testament; for they proceed from the mouth of God Himself.
We divided this Word into two principal parts or kinds: the one is called the “Law”, the other the “Gospel.” For, all the rest can be gathered under the one or the other of these two headings.
What we call Law (when it is distinguished from Gospel and is taken for one of the two parts of the Word) is a doctrine whose seed is written by nature in our hearts. However, so that we may have a more exact knowledge, it was written by God on two Tables and is briefly comprehended in ten commandments. In these He sets out for us the obedience and perfect righteousness which we owe to His majesty and our neighbours. This on contrasting terms: either perpetual life, if we perfectly keep the Law without omitting a single point, or eternal death, if we do not completely fulfill the contents of each commandment (Deut. 30:15-20; James 2:10).
What we call the Gospel (“Good News”) is a doctrine which is not at all in us by nature, but which is revealed from Heaven (Matt. 16:17; John 1:13), and totally surpasses natural knowledge. By it God testifies to us that it is His purpose to save us freely by His only Son (Rom. 3:20-22), provided that, by faith, we embrace Him as our only wisdom, righteousness, sanctification and redemption (1 Cor. 1:30). By it, I say, the Lord testifies to us all these things, and even does it in such a manner that at the same time He renews our persons in a powerful way so that we may embrace the benefits which are offered to us (1 Cor. 2:4).