Genesis 6:18 - Ellicott's Commentary On The Whole Bible

My covenant. — There had been no covenant with Adam or with the Sethites, but in the higher state of things which began with Noah, man was to hold a more exactly defined relation to God; and though they had begun to attach the notion of Deity to the name Jehovah in the days of Enos (Genesis 4:26), yet it was not till the time of Moses that it became the distinct title of God in covenant with man. Of this relation a necessary result was revelation, as in no other way could there be a communication between the two contracting parties. Hence the Bible is called “The Old and New Covenant,” or “The Old and New Testament,” the Greek term being of wider meaning than either word with us, and signifying either an agreement between the living or the document by which a testator disposes of his property after his death (Hebrews 9:16-17). The title of covenant is more applicable to the Scriptures of the prior dispensation, which contain a series of such relations, all preparing for the last and best and most perfect, which was a Testament ratified in the blood of Christ.