From Muller's preface: "In the preface to the two volumes of Reformed Dogmatics, dated October 31, 1931, Berkhof notes his use of Bavinck but registers especially the importance of the theology of Geerhardus Vos to his own development."
Louis Berkhof has never thrilled me as a systematician. Herman Bavinck described the theology of Francis Turretin as mere reproduction lacking productive power. I tend to think that could be said of Berkhof even more so than Turretin.
In the case of Berkhof we have not only a lack of "productive power" but also some apparent "copying".
Below, Berkhof directly depends upon Vos on a certain topic (i.e., the Mosaic covenant). The similarities are striking, but in a way that makes me a little uncomfortable given our standards today for what constitutes plagiarism. This is one of many examples I could give from Berkhof's ST. Berkhof does much the same, even on a greater scale, with Bavinck.
Berkhof (p. 298, Banner ed.; bold used to highlight particular similarities):
a. At Sinai the covenant became a truly national covenant. The civil life of Israel was linked up with the covenant in such a way that the two could not be separated. In a large measure Church and State became one. To be in the Church was to be in the nation, and vice versa; and to leave the Church was to leave the nation. There was no spiritual excommunication; the ban meant cutting off by death.
Vos (vol. 2, p. 129):
a) Now, for the first time, the covenant with Israel rightly became a national covenant. The social life of Israel, its civil organization, its existence as a people, were brought directly into contact with the covenant of grace. These two were inextricably linked. One cannot say, "I want to leave the Jewish church but remain in the Jewish state." Whoever left the church left the state. And one could leave the state only by being exterminated from the people. Properly speaking, there is discipline through censure in a certain sense, but not, properly speaking, discipline only through excommunication or cutting off from the church. The sanction was the death penalty. All this first came about at Sinai. Earlier, God Himself had cut off Ishmael and Esau from the covenant administration. Judicially, this is later no longer permitted.
b. The Sinaitic covenant included a service that contained a positive reminder of the strict demands of the covenant of works. The law was placed very much in the foreground, giving prominence once more to the earlier legal element. But the covenant of Sinai was not a renewal of the covenant of works; in it the law was made subservient to the covenant of grace. This is indicated already in the introduction to the ten commandments, Ex. 20:2; Deut. 5:6, and further in Rom. 3:20; Gal. 3:24. It is true that at Sinai a conditional element was added to the covenant, but it was not the salvation of the Israelite but his theocratic standing in the nation, and the enjoyment of external blessings that was made dependent on the keeping of the law, Deut. 28:1-14. The law served a twofold purpose in connection with the covenant of grace: (1) to increase the consciousness of sin, Rom. 3:20; 4:15; Gal. 3:19; and (2) to be a tutor unto Christ, Gal. 3:24.
b) The covenant with Israel served in an emphatic manner to recall the strict demands of the covenant of works. To that end, the law of the Ten Commandments was presented so emphatically and engraved deeply in stone. This law was not, as Cocceius meant, simply a form for the covenant of grace. It truly contained the content of the covenant of works. But--and one should certainly note this--it contains this content as made serviceable for a particular period of the covenant of grace. It therefore says, for example, "I am the Lord your God." Therefore, it also contains expressions that had reference specifically to Israel, and thus are not totally applicable to us (e.g., "that it may be well with you in the land that the Lord your God gives you"). But also, beyond the Decalogue, there is reference to the law as a demand of the covenant of works (e.g., Lev 18:5; Deut 27:26; 2 Corinthians 3:7, 9). It is for this reason that in the last cited passage, Paul calls the ministry of Moses a ministry of condemnation. This simply shows how the demand of the law comes more to the fore in this dispensation of the covenant of grace. This ministry of the law had a twofold purpose: (1) It is a disciplinarian until Christ. (2) It serves to multiply sin--that is, both to lure sin out from its hidden inner recesses as well as to bring it to consciousness (cf. Gal 3:19; Rom 4:15; 5:13). Paul teaches expressly that the law did not appear here as an independent covenant of works in Galatians 3:19ff. That the law is also not a summary of the covenant of grace appears from the absence of the demand of faith and of the doctrine of the atonement.
c. The covenant with the nation of Israel included a detailed ceremonial and typical service. To some extent this was also present in the earlier period, but in the measure in which it was introduced at Sinai it was something new. A separate priesthood was instituted, and a continuous preaching of the gospel in symbols and types was introduced. These symbols and types appear under two different aspects: as the demands of God imposed on the people; and as a divine message of salvation to the people. The Jews lost sight of the latter aspect, and fixed their attention exclusively on the former. They regarded the covenant ever increasingly, but mistakenly, as a covenant of works, and saw in the symbols and types a mere appendage to this.
c) The covenant with Israel had a ceremonial and a typical ministry, fixed in its details. That was also already so in part for the earlier administration of the covenant of grace. But to the degree that it now came about, that ceremonial ministry was something new. A formal gospel preaching was offered continually by symbols and types. A priestly class came into existence. Earlier, every father of a family was a priest. Now, particular persons are separated and consecrated for this function. One must consider all these types and symbols from two points of view: (1) as demands of God on the people; (2) as a proclamation of God to the people. God had appointed them to serve in both respects. But the Jews overlooked the latter aspect more and more and made the types and symbols exclusively serve the former purpose. That is to say, they used them only as additions to a self-willed covenant of works, and misunderstood the ministering significance they had for the covenant of grace. So the opinion arose that righteousness had to be obtained by keeping that law in the broadest sense of the word, including the ceremonial law. And by this misuse, the covenant of grace of Sinai was in fact made into a Hagarite covenant, a covenant giving birth to servitude, as Paul describes it in Galatians 4:24. There he has in view not the covenant as it should be, but as it could easily become through misuse.
d. The law in the Sinaitic covenant also served Israel as a rule of life, so that the one law of God assumed three different aspects, designated as the moral, the civil, and the ceremonial or religious law. The civil law is simply the application of the principles of the moral law to the social and civic life of the people in all its ramifications. Even the social and civil relations in which the people stood to each other had to reflect the covenant relation in which they stood.
d) The law given by God also served as a rule of life for Israel. So, we obtain a threefold law: the moral, the ceremonial, the civil law. This civil law was a particular application of the principles of the moral law. For example, in the moral law God says in general, "You shall not steal." The civil law further elaborates what constitutes stealing, what penalties apply, etc., etc. At the same time, this law as a rule of life for civil concerns was elaborated in such a way that it provided a model for the spiritual relationship to God of the members of the covenant. Israel must bring its tithes, firstfruits, drink- and vow-offerings; and in doing that the dedication of the covenant member to God was also foreshadowed in the covenant of grace. No one from Israel may be a slave, for every Israelite is as such already totally God's possession. Even the land of the children of Israel is God's property; they are merely sojourners and aliens toward God, who live from what is His. So, too, in civil relationships in Israel, in the civil side of the covenant, the essence of the covenant of grace is mirrored.
Now, for some context:
First, these texts were both first used as syllabi for students at what came to be Calvin Theological Seminary. They used Vos as a textbook even after he left go to Princeton. Perhaps Berkhof took the existing syllabus and updated it in light of his own analysis and recent opinion. So there are sections where he "borrows" pretty thoroughly, even copies almost word-for-word, as the evidence above shows.
Almost verbatim quotations from his predecessors is unsurprising because the origin of the Systematic Theology arose from students taking down notes of his lectures. They then transcribed them, turned in mimeographs, and the lectures were printed up for classroom use. Eventually they were edited into the book we now have.
Second, there's also a linguistic factor here. Vos wrote his dogmatics in Dutch, whereas Berkhof was writing when the church was self-consciously trying to switch to English in preaching and theological writing. So in one way, Berkhof is giving a a kind of periphrastic translation of Vos (and Bavinck).
Third, Berkhof regularly cites the parallel sections of Vos's dogmatics at the end of his chapters. This is true of the chapter on the Mosaic covenant. The citation wouldn't be acceptable today by our standards, though. And I certainly would like to see a little more credit given to his sources. Simply citing a "Literature" section at the end of the chapter is not sufficient today. In fact, one finds more extensive citations in many 16th and 17thC dogmatic texts.
Fourth, Berkhof was a student of Vos. Who knows what kind of note-taking he did. We might need to ask how much of Vos comes out of Aegidius Francken's Stellige God-geleertheyd (3 vols) or Francken's Kern der Christelijke Leer.
If Berkhof were doing this today, I think he'd be in real trouble. And if one of my students did this today, he'd end up having a very uncomfortable discussion with me. But, to be fair to Berkhof - whom I tend to think was not a very original thinker, but still a very good summarizer - he lived in a particular social and ecclesiastical context.
So an initial glance at Berkhof and Vos might cause one to be very concerned. But, as is often the case, there's a lot of information that needs to be considered. Not having lived in that context, of course, there are likely even more details missing from my own analysis.
When it comes to exposing plagiarism, we inevitably find that things are always a little more complicated when our analysis goes beyond mere pasting of different sources side-by-side.
Whatever one's feelings on the above - and several scholars offered slightly different reactions to my findings - Berkhof would probably say a hearty "Amen" to Hodge's famous quip: "I am not afraid to say that a new idea never originated in this Seminary."