If the most ultimate meaning of marriage is to represent the unbreakable covenant-love between Christ and His church (Ephesians 5:22-33), then no human being has a right to break a marriage covenant. When the impossible day comes that Christ breaks His vow, “I am with you always, to the end of the age” (Matthew 28:20), then, on that day, a human being may break his marriage covenant. This explains why Jesus does not settle for the divorce provision of Deuteronomy 24:1-4 (Mark 10:3-9), but says, “What therefore God has joined together, let not man separate” (Mark 10:9). In other words, since God is the One who decisively makes every marriage, only God has the right to break a marriage. And He does it by death. Which is why the traditional and biblical marriage vows have one and only one limitation: “till death do us part,” or, “as long as we both shall live.”
John Piper