Ursinus: Christ Was The Author And Mediator Of The Old Covenant


Since there is but one covenant, and the Scriptures speak of it as though it were two, we must consider in what particulars the old and the new covenants agree and in what they differ.

They agree,

1. In having God as their author and Christ as the Mediator. But Moses, some say, was the Mediator of the Old covenant. To this we reply, that he was Mediator only as a type of Christ, who was even then already Mediator, but is now the only Mediator without any type; for Christ having come in the flesh, is no longer covered with types.

2. In the promise of grace concerning the remission of sins, and eternal life granted freely to such as believe by and for the sake of Christ, which promise was common to those who lived under the old covenant, as well as to us; although it is now delivered more clearly, for God promises the same grace to all that believe in the Mediator. “The seed of the woman shall bruise the serpent’s head.” “I will be a God unto thee and thy seed.” “He that believeth on the Son hath everlasting life.” “But we believe that through the grace of the Lord Jesus Christ, we shall be saved even as they.” (Gen. 3:15; 17:7. John 3:36. Acts 15; 11.) We here speak of the promise of grace in general, and not of the circumstances of grace particularly.

3. In the condition in respect to ourselves. In each covenant, God requires from men faith and obedience. “Walk before me and be thou perfect.” “Repent and believe the gospel.” (Gen. 17:1. Mark 1:15.) The new covenant, therefore, agrees with the old in that which relates to the principal conditions, both on the part of God, and on the part of man.

The two covenants differ,

1. In the promises of temporal blessings. The old covenant had many special promises in relation to blessings of a temporal character, such as the promise of the land of Canaan, which was to be given to the Church—the form of the ceremonial worship, and of the Mosaic polity, which were to be preserved in the land even to the time of the Messiah—the birth of the Messiah from that people, &c. But the new covenant has no such special promises of temporal blessings, but only such as are general, because God will preserve his church even to the end, and will always provide for it a certain resting place.

2. In the circumstance of the promise of grace. In the old covenant, the faithful were received into the favor of God, on account of the Messiah that was to come, and the sacrifice which he would offer; in the new, the same blessing is obtained for the sake of the Messiah who has already come, and for the sacrifice which he has already offered in our behalf.

3. In the rites, or signs, which are added to the promise of grace. In the old covenant the sacraments were various, and painful, such as circumcision, the passover, oblations and sacrifices. In the new, there are only two sacraments—Baptism and the Lord’s Supper—both of which are simple and significant.

4. In clearness. The old had types and shadows of good things to come. All was typical, as the priests, sacrifices, &c. Hence every thing was more obscure and unintelligible. In the new, we have a fulfillment of all these types, so that every thing is clearer and better understood, both in regard to the sacraments and the doctrine which is revealed.

5. In the gifts which they confer. In the old, the effusion of the Holy Spirit was small and limited; in the new, it is large and full. “I will make a new covenant.” “If the ministration of condemnation be glory, much more,” &c. “I will pour out my Spirit upon all flesh.” (Jer. 31:31. 2 Cor. 3:5. Joel 2:28.)

6. In duration. The old was to continue only until the coming of the Messiah; but the new will continue forever. “I will make an everlasting covenant with them.” (Jer. 32:40.)

7. In their obligation. The old bound the people to the whole law, the moral, ceremonial, and judicial; the new binds us only to the moral, and to the use of the sacraments of Christ.

8. In their extent. In the old covenant, the church was confined to the Jewish nation, to which it became all those who would be saved to unite themselves. In the new, the church is established among all nations, and is open to all that believe of every nation, rank, condition, or language.

Remark. The old testament, or covenant, is often used in Scripture by a figure of speech, called synecdoche, (in which a part is taken for the whole,) for the law, with respect to that part which is especially treated of. For in the old covenant, the law was enforced more strenuously, and there were many parts of it. The gospel was also more obscure. The new testament, or covenant, on the other hand, is for the most part taken for the gospel, because in the new a great part of the law is abrogated, and the gospel is here more clearly revealed

Zacharias Ursinus, The Commentary of Dr. Zacharias Ursinus on the Heidelberg Catechism, trans. G. W. Willard (Cincinnati, OH: Elm Street Printing Company, 1888), 99–100 [commenting on Heidelberg Catechism 18]


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  • R. Scott Clark
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    R.Scott Clark is the President of the Heidelberg Reformation Association, the author and editor of, and contributor to several books and the author of many articles. He has taught church history and historical theology since 1997 at Westminster Seminary California. He has also taught at Wheaton College, Reformed Theological Seminary, and Concordia University. He has hosted the Heidelblog since 2007.

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