Charles Ellicott Commentary Genesis 6:18

"But I will establish my covenant with thee; and thou shalt come into the ark, thou, and thy sons, and thy wife, and thy sons` wives with thee." — Genesis 6:18 (ASV)

My covenant. —There had been no covenant with Adam or with the Sethites, but in the higher state of things that began with Noah, humanity was to hold a more precisely defined relation to God. And though people had begun to attach the notion of Deity to the name Jehovah in the days of Enos (Genesis 4:26), it was not until the time of Moses that Jehovah became the distinct title of God in covenant with humankind. A necessary result of this relation was revelation, as in no other way could there be communication between the two contracting parties.

Therefore, the Bible is called “The Old and New Covenant,” or “The Old and New Testament.” The Greek term has a wider meaning than either word in our language; it signifies 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 “covenant” is more applicable to the Scriptures of the prior dispensation. These Scriptures contain a series of such relations, all preparing for the last, best, and most perfect one—a Testament ratified in the blood of Christ.