Is New Testament the same as New Covenant?

What is the difference between “Testament” and “Covenant”? In the Western world, many people are familiar with a “final will and testament” — a legal document read when someone passes away. The document expresses the deceased’s wishes, often in connection with estate and inheritance. As a unilateral declaration of one’s will, a “testament,” in this sense, is not the same as a “contract” or “pact,” which necessitates an agreement between two or more parties. The author of Hebrews makes an appeal to this Greek term to show that a “testament” (διαθήκη; diatheke) is initiated only after death (Heb 9:16-17).

The English theological term “New Testament” comes from the Latin Novum Testamentum – The Latin for “New Testament” translates the Greek phrase καινὴ διαθήκη (kaine diatheke) that appears in the Septuagint (Jer 31:31 LXX; cf. Lk 22:20). Yet, upon closer examination, the original Hebrew term for “covenant” (בְּרִית; berit) does not line up exactly with the idea of “testament” (διαθήκη; diatheke). So why would this Greek word be used in Luke, Hebrews, and 1 Corinthians (Lk 22:20, Heb 8:8; 9:11–15, Cor 11:25)? Hard to say, but perhaps they merely followed in the footsteps of the translators of the Jewish Bible into Greek who felt that this was the best word to translate the Hebrew “covenant” (בְּרִית; berit). But translations are the work of human authors! They do the best they can to find fair equivalents.