In his great work, Economy of the Covenants Between God and Man, Herman Witsius outlines several benefits of the New Testament. The second of which is, “the gospel of the kingdom…namely, the gospel as completed” (see first).
We should never think that under the Old Testament people were saved in one way, and in the New another way. What is true of New Testament believers is true of Old Testament believers, that Jesus Christ is the only way to the Father and salvation is only by faith in him. When Paul wanted to prove the glorious doctrine of justification by faith alone he used God’s dealing with Abraham as paradigmatic. Likewise, the author of Hebrews speaks to the unity of the “old” and “new” in Hebrews 11, “that apart from us they should not be made perfect” (v. 40), and they too had the gospel preached to them (4:2). So the Old Testament saints had the gospel. But they gospel they had preached to them was a proclamation of future grace, whereas under the New Testament we have a completed gospel, the work is finished.
But what is the great benefit of having the gospel as complete? Witsius helpfully deals with this under four headings:
- The gospel we preach sets forth things as fulfilled, which were formerly foretold would come to pass. While God’s Word is always sure, and so the Old Testament saints had an unwavering confidence in the promise to come (Romans 4:20-21), to have that Word now fulfilled in time, certainly bolsters our faith.
- The gospel is now announced with a clarity that was before masked in “the labyrinths of dark sayings.”
- While the covenant of grace has, throughout redemptive history, been one it has been diversely administered. The Westminster Confession of Faith rightly says, “This covenant was differently administered in the time of the law, and in the time of the Gospel” (7.5). There was, in the Old Testament, more of a legal character to the covenant of grace, that was attended upon with more severity and rigor. It is not so now, but rather the heart is allured, Witsius says, with the sweetest and most abundant consolations.
- In his own words, “That it dwells now more abundantly in us, and is preached more fully and frequently, and with a greater demonstration of the Spirit, and a deeper insinuation or sinking into the conscience (Romans 10:8).”