The Bible clearly teaches that God made several distinct covenants with mankind. Writing in Romans 9:3-4 of his “kinsmen according to the flesh” Paul refers to “the covenants” (plural). Also in Galatians chapter four he writes of “two covenants” (Galatians 4:21-31). There he is referring to the Old Covenant made with Israel and the New Covenant. These covenants are quite distinct. In Genesis chapter nine we read of the covenant made with Noah, never to flood the earth again. There were no conditions and the sign was the rainbow in the clouds, obviously linked with the subject of rain. This covenant was quite separate from the others which God made. Even if no other covenants had been made this covenant would have stood, as indeed it still does.
Then there was the covenant made with Abram in Genesis 15 and 17. In this covenant God made two promises; He promised a multitude of descendants and the land of Canaan as a permanent possession. The covenant sign was circumcision, obviously symbolically connected with the promise of a multitude of offspring. This was the covenant that Moses refers to as made with “the fathers” (Deut. 4:3).
The next covenant was made through Moses with the nation of Israel. It stated that they should be a special treasure to God above all peoples, a kingdom of priests and a holy nation (Exod. 19:5, 6). At the same time a series of laws was given to Israel which they were obliged to keep as their part in the covenant (Exod. 19-31). Prominent among these laws were the Ten Commandments. These were especially linked with this covenant as is seen in various designations given them. They are called in the Old Testament “the words of the covenant” (Ex. 34:28), “His covenant” (Deut. 4:13,14), “the tablets of the covenant” (Deut.9:9, 11, 15), and even “the covenant” (I Kings 8:21; II Chron. 6:11). In the New Testament they are referred to in Hebrews 9:4 as “the tables of the covenant.” In neither Old nor New Testament are they ever called “the moral law.”
There are two important things to notice about this covenant made through Moses. First of all, Moses explicitly says that “the Lord did not make this covenant with our fathers, but with us, those who are here today, all of us who are alive.” (Deut. 5:1-3). This covenant was therefore distinct from the covenant made with Abram, although they benefitted from Abram’s covenant in that they inherited the Promised Land (Deut. 4:31). The second thing to point out is that the sign of the covenant made with Israel at Horeb was the Sabbath. As was often the case with Near Eastern treaties and covenants, the sign of the covenant was embedded in the stipulations. The Lord spoke to Moses, saying, “Surely my Sabbaths you shall keep, for it is a sign between Me and you throughout your generations as a perpetual covenant.” (Exodus 31:12-18, cf. Ezekiel 20:12, 20).
The next passage to consider is the famous prophecy in Jeremiah (Jer. 31:31-34). Here again the Lord expressly states that this is a “new” covenant, and that it is “not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt…” Clearly this “new covenant” is to be distinct from the covenant made at Sinai. This is fully confirmed in the New Testament.
First, our Lord announced this new covenant in His blood when He instituted the Lord’s Supper (Luke 22:20). Secondly, the Apostle Paul contrasted the new covenant and the old covenant in The Second Epistle of Paul to the Corinthians, chapter three. He states that the old covenant letter kills (v. 6), but the Spirit gives life. The old covenant was a ministry of death, and though it was in some senses glorious, the ministry of the Spirit is more glorious (vv. 7-9). Thirdly, Paul contrasts the “two covenants” in Galatians, chapter four, verses 21-31.
Then in the Epistle to the Hebrews, where Jeremiah’s prophecy is quoted (8:7-13), the author refers to “a better covenant” (7:22; 8:6) because the old covenant was faulty in that the Israelites failed to keep it (8:7, 8). That first covenant is “obsolete and growing old…ready to vanish away’ (8:13). Christ is the mediator of the new covenant (9:15).
It could hardly be stated more clearly that the new covenant is different, distinct, not the same as the old covenant. It is not the same covenant under a new dispensation. The covenants are distinct and it is an error to blur the differences and seek to “paper over the cracks.” The Old Testament sacrifices were types and shadows of Christ and His death on Calvary. But that is all they are. They cannot take away sins (Heb. 10:1-4). Only Christ’s one, sufficient and perfect sacrifice could take away sin. And His blood, symbolized in the cup at Communion, is the sign of the new, distinct, different covenant. Neither can the old covenant bring the glorious freedom that Christ through the Spirit brings in the new covenant.
Where did this idea of one over-arching covenant come from? You cannot find it in the Bible. It was conceived first of all by Ulrich Zwingli (1484-1531) the Swiss reformer, as a justification for holding on to the practice of infant baptism.
When the Reformers gradually separated from the Church of Rome, they discarded many Roman errors one by one. But they did bring various items of Roman baggage over with them. Included in this carry-over from Rome were two significant beliefs and practices. One was the idea of a “sacral society”. A sacral society exists when there is a very close tie between the state and religion. Sometimes the state controlled religion, sometimes the religion controlled the state. Israel was, of course, a sacral society. Europe was also, at the time of the Reformation, and the various countries in Europe were dominated by the pope. The other item the Reformers clung to was infant baptism.
Zwingli led a group of zealous Swiss reformers, priests and intellectuals, who were seeking to rid the “believers’ church” of Roman errors. One by one they discarded false teachings and practices. They came to the matter of baptism. Zwingli was unhappy about infant baptism, but he was more cautious than the group around him. He actually confessed in his early days: “Nothing grieves me more than that at the present I have to baptize children, for I know it ought not to be done.”  His compatriots not only wanted to return to the biblical practice of believer’s baptism, they also wanted to separate church and state. This alarmed Zwingli. He was afraid that such a move would disrupt the Reformation. He held to the idea of a sacral society. He debated baptism with the other Swiss brethren in a public debate. After the debate the city council ruled that Infant Baptism was the correct form. Dutifully Zwingli accepted their decision. The Sacral Society strikes again!
So Zwingli withdrew from his interest in believer’s baptism and looked around for a justification for baptizing infants. He knew there was no New Testament basis for it, so he came up with the idea of one over-arching covenant of which the various covenants were but aspects. This meant that just as (male) babies were circumcised under the old covenant, so they could be baptized under the new covenant. The idea of a parallel between circumcision and baptism had been thought of before, but never on a covenantal basis. Zwingli’s successor, Heinrich Bullinger, took up the idea, followed by Calvin, and so Covenant Theology was born. But there is really no biblical justification for it, though many attempts have been made to find one, especially by trying to interpret three New Testament passages to justify the baptism of infants.
First of all, Acts 2:39 is claimed to open the way for infant baptism. The verse states: “For the promise is to you and to your children, and to all who are afar off, as many as the Lord our God will call.” The first thing we should notice is that this promise also applies to “all that are afar off.” In other words, this promise is also given to the Gentiles, the heathen, all who are afar off. Next we observe that the promise is given to “as many as the Lord our God will call.” In other words, this promise is not only to our children but to everyone else, but it depends upon the effectual call of God. But what is this promise? It is found in the previous verse, which states, “Repent, and let every one of you (i.e., those who had cried out ‘What shall we do?), be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit.” It all hangs upon the call of God and the repentance of those called. There is no way that verse justifies the baptism of unconscious, unrepentant babies, or unrepentant Gentiles, for that matter. They must repent (and believe which is implied in the context) to be saved when God calls them.
A second verse which is pressed into service to justify infant baptism is I Corinthians 7:14. This verse does not mention baptism, and in fact has nothing to do with baptism. It is intended to help Christians who are married to unbelievers. Presumably they had been converted since marrying an unbeliever (or they should not have done so if already believers). The question dealt with is, should they leave the unconverted spouse? Is the marriage valid? This is, admittedly, a difficult verse, and the meaning hangs upon the word “sanctified”. Whatever it means, it does not mean “saved” as it applies to the unbelieving spouse as well as the children. Few, if any, interpreters would claim that an unbeliever is saved by being married to a Christian. The best solution seems to be to take the word “sanctified” as meaning “set apart” in some sense; set apart to a genuine marriage, to a Christian influence. The word “unclean’ surely means “illegitimate” here; if the marriage is invalid the children would be illegitimate. But if the marriage is in order they are legitimate. But the verse has nothing at all to do with baptism. It merely assures Christians married to non-Christians that their marriage is valid, even though their spouse is not a believer.
The third passage chosen to defend infant baptism is Colossians 2:11-13 in which the words ‘circumcision’ and ‘baptism’ are found in two contiguous verses. But here again, these verses in no way link physical circumcision with baptism, nor do these words make them parallel in meaning. The ‘circumcision’ in verse 11 is made “without hands” and is performed by Christ. It consists in “putting off the body of the sins of the flesh,” which is surely conversion not physical circumcision performed by a priest. This is followed by being “buried with Him in baptism.” Who are these people in the context? They have received Christ as Lord (v. 6) and are complete in Him (v. 10). They have been made alive from being dead in trespasses (c. 13). It is really only in desperation that one could claim that this passage justifies infant baptism.
Many people accept Covenant Theology because it was taught them, not because they have found it by studying the Scriptures. Most have never really examined the basis for it. Many accept it because it is taught in the Westminster Confession of Faith and that is their accepted standard. Creeds and confessions can be useful, but we do need to be careful in relying too heavily upon them. For one thing the many confessions differ from one another, sometimes in small matters such as phraseology, sometimes in major doctrines. It is most important that we do not judge Scripture in the light of our chosen Confession. After all, the Confessions are man-made documents. They are not inspired. Useful they may be for some purposes, but they must never replace the Scriptures. They must be judged by the Scriptures and not the other way round.
People often confuse God’s covenants, made with man in time, which are all distinct, with God’s purpose. God’s purpose in creation and redemption, etc., is a different thing altogether from the various covenants He has made with man. Each covenant has a part to play in God’s plan, but neither one covenant nor all together should be confused with God’s eternal purpose. It is this confusion which has muddied the waters and led many astray.
 Cited in Leonard Verduin: The Reformers and their Stepchildren, p. 198.