A recent discussion brought up the Greek term for the word “covenant.” Well, actually, two words were brought up, but only one of them applied. What I heard in the moment didn’t ring true to my recollection of what I’d studied in the past, so I decided to pursue the subject on my own.
In my subsequent (re)study of the terminology, I refreshed my memory, confirmed some suspicions and learned something new. So, all in all, it has been a good thing for me. I considered writing an excursus on the two Greek words in question, then even began writing in detail about the Biblical concept of “covenant.”
But in the end, it’s a distraction from my translation work, which I need to get back to. So, I’m just going to do a quick blog about this and let it go at that.
Those two Greek words are συνθήκη and διαθήκη. I know that many reading this do not read Greek and are unfamiliar even with the characters of the Greek alphabet. So, let me just get this out of the way, since many of you are thinking it: “It’s all Greek to me.”
Okay, getting (a little) more serious about the problem of the unfamiliarity of Greek characters, let me transliterate those two terms. Transliteration is the process of spelling words from one language in the characters of another language. Of course, in this case, from Greek to English. So, about these two words, συνθήκη = sunthēkē, and διαθήκη = diathēkē.
(These words, by the way, are quite old, and yet still in use. In Modern Greek, sunthēkē means treaty or convention. As for diathēkē, that refers to a testament or will. “The Old Testament” in Modern Greek is Ē Palaia Diathēkē [Η Παλαιά Διαθήκη], and “The New Testament” is Ē Kainē Diathēkē [Η Καινή Διαθήκη].)
The understanding of these two terms as presented in that aforementioned discussion maintained that sunthēkē was the more common word of the two, and that it meant something on the order of “two-sided agreement.” By contrast, the claim was that diathēkē was a rare word, with a meaning something on the order of “one-sided agreement.”
As for the respective meanings of the two terms, it’s an oversimplification, but has some basis in fact. I won’t go into the meanings any more than that. To do so would require me to do an in-depth article. However, as for the frequency of the occurrence of these terms, the idea presented that sunthēkē is a common word while diathēkē is a rare word is just plain wrong. A relatively simple and straightforward presentation of the facts should clear this up.
Sunthēkē, the supposed common word, is not used at all in the Greek New Testament (hereafter, GNT). Furthermore, it is not found in post-Biblical/early Christian writings. It does occur four times in the canonical books of the Septuagint, the ancient Greek translation of the Hebrew Scriptures (hereafter abbreviated LXX). If instances of sunthēkē occurring in the apocryphal books of the LXX are included, the total rises to thirteen. In classical and secular Greek, sunthēkē basically referred to “a composition, esp. of words and sentences…but commonly” was used in the plural for articles of agreement, and collectively, of a contract, compact, covenant, treaty.”
So sunthēkē was a common word in classic Greek (Thucydides, Xenophon, Plato, et al.) and later secular Greek literature. But as for Biblical usage, in the LXX, it was a rare word, and it was not used at all in the GNT or in post-Biblical Christian writings.
Now let’s consider the other Greek term, diathēkē. It is also as old as the Greek classics. Aristophanes, for example, used it in his plays. Dinarchus and Lysias used it in their speeches. It is used 314 times in the canonical books of the LXX. If instances of diathēkē occurring in the apocryphal books of the LXX are included, the total rises to 353. In the GNT, diathēkē is used 33 times. It is also found numerous times in post Biblical/early Christian writings. It is also found in Josephus and Philo, and is a loanword in rabbinical literature.
So, while sunthēkē was a common word in the classical period of Greek literature, diathēkē was by no means a rare word or a relatively new word. Both terms were in use at least from the time of the fourth century before Christ. And when it comes to the LXX, diathēkē was a common word used hundreds of times while sunthēkē rarely occurred. And in the GNT and beyond, diathēkē is both a common and enduring word, while sunthēkē, by contrast, fell out of use.
The second aspect of this controversy in the discussion has to do with the source of the information. It was a commentary by William Barclay (1907-1978), a Church of Scotland clergyman and professor of textual criticism. I did not know at first that this was the source of the misinformation. I would have been even more suspicious had I known that, because of my knowledge of Barclay’s views and his commentaries.
Don’t let his status as a clergyman and professor fool you; Barclay was a notorious unbeliever. From his own writings, his commentaries and his autobiography, it is clear that Barclay: routinely rejected the miracles recorded in the Gospels; professed to be an evolutionist; professed himself to be a universalist; and he outright rejected the deity of Christ.
I learned years ago to be strenuously discriminating when it comes to quoting resources in Bible teaching. And so I don’t use Barclay or refer to him, except in the form of an exposé of error. Another example is the publisher of Barclay’s commentaries, the Westminster John Knox Press. They routinely publish works that undermine faith in Biblical truth.
So my takeaway from this is a lesson in diligence concerning Biblical commentaries. The facts concerning the two Greek words for “covenant” were misrepresented, and the basis for this information was from a source that is best to consider post-Christian.
 In documenting numbers of occurrences for each of these Greek words (sunthēkē and diathēkē) in Biblical bodies of literature, I used the search features of my BibleWorks8 software. For references to post-Biblical/early Christian writings, BibleWorks8 again searches some of these works, and BAGD covers this period of Greek writings as well: Walter Bauer, William F. Arndt, F. Wilbur Gingrich & Frederick W. Danker [BAGD], A Greek-English Lexicon of the New Testament and Other Early Christian Literature, 1958, 1979, page 183.
 Henry George Liddell & Robert Scott, A Greek-English Lexicon. Seventh Edition, Revised and Augmented throughout. 1889, p. 1493.
 Liddell-Scott, p. 346.
 BAGD, p. 193.