Covenant begins with God binding himself to a promise no one asked him to make. After the flood, he pledges to Noah that he will never again destroy the earth by water — a promise that depends on nothing Noah does, sealed by a rainbow set in the sky as a permanent sign. That same unconditional shape marks God's covenant with Abraham: in a ceremony where only God himself passes between the divided animals, he takes the entire weight of the promise — land, offspring, and blessing to every nation — onto his own word alone.
At Sinai, the covenant takes on a different shape. Freshly rescued from Egypt, Israel is bound to God on conditional terms: obey, and live as his treasured people. But Israel could not keep what it promised, and centuries of failure exposed a problem no better law could fix. Through Jeremiah and Ezekiel, God announces a new covenant that will succeed where the old one failed — not by tightening the terms, but by writing his law on the heart itself and placing his own Spirit within his people.
Jesus ratifies this new covenant in the most personal terms possible: not with the blood of animals thrown on an altar, but with his own blood, given to his disciples to drink at the table the night before he died. His death accomplishes what centuries of sacrifice could never finish, and Revelation carries the covenant to its final form — the ancient promise ‘I will be their God, and they will be my people’ realized forever, with nothing left to threaten it.