The Heb. berith means primarily "a cutting," with reference to the custom of cutting or dividing animals in two and passing between the parts in ratifying a covenant. (Genesis 15; Jeremiah 34:18,19)
In the New Testament the corresponding word is diathece (diatheke), which is frequently translated testament in the Authorized Version. In its biblical meaning two parties the word is used-
• Of a covenant between God and man; e.g. God covenanted with Noah, after the flood, that a like judgment should not be repeated. It is not precisely like a covenant between men, but was a promise or agreement by God. The principal covenants are the covenant of works-God promising to save and bless men on condition of perfect obedience-and the covenant of grace, or God's promise to save men on condition of their believing in Christ and receiving him as their Master and Saviour.
The first is called the Old Covenant, from which we name the first part of the bible the Old Testament, the Latin rendering of the word covenant. The second is called the New Covenant, or New Testament.
• Covenant between man and man, i.e. a solemn compact or agreement, either between tribes or nations, (Joshua 9:6,15; 1 Samuel 11:1) or between individuals, (Genesis 31:44) by which each party bound himself to fulfill certain conditions and was assured of receiving certain advantages. In making such a covenant God was solemnly invoked as witness, (Genesis 31:50) and an oath was sworn. (Genesis 21:31) A sign or witness of the covenant was sometimes framed, such a gift, (Genesis 21:30) or a pillar or heap of stones erected. (Genesis 31:52)