In today's first reading, God renews with Noah the covenant that he had made with Adam and Eve. Notice the change, though: He replaced the commandment about not eating from the Tree of Knowledge with a commandment about not eating animal flesh that still has "its lifeblood" in it. This will be further renewed when he makes the covenant of Moses.
God is still renewing covenants today. When we sin, we turn away from God, but he's always eager to restore the relationship. Since things can never be the same again, thanks to the damage we caused by our sins, we need a new, enhanced covenant.
For example, years ago when a friend betrayed me, I was filled with resentment and wanted to drive him out of my life. However, God wanted me to obey the Christian commandment about loving our enemies. So I wanted to know: "If there's no indication that this fellow is going to overcome the problems that are harming our relationship, why stay in this mess? It's hopeless!"
Then one day, as my husband and I were driving to a store, God showed us a rainbow. I said to Ralph sarcastically, "Oh goodie, look at that. A rainbow. God is telling us not to give up. R-i-i-i-ight." We turned the car in a different direction and there in front of us was another rainbow.
"Okay, I get it!"
The rainbow became a symbol of my new, enhanced covenant with the Lord. By relying on his supernatural love, I could love the troublesome friend unconditionally even while the relationship continued to disintegrate. I could keep trying to help him until God, instead of my resentment, told me to stop. And he did, a few years later, at which time I was able say good-bye in a spirit of forgiveness, knowing that God would try to help him some other way now.
God is sovereign. His plans always succeed, but sometimes people interrupt Plan A, and so he comes up with Plan B. That's what happened in the Garden of Eden. Plan A was a holy life in paradise. Noah's Ark was part of Plan B, but that didn't keep us holy either. Eventually, God gave us Plan J (Jesus). The new covenant is to love as Jesus loves.
Who do you say Jesus is? This is the question for us in today's Gospel reading. Is he truly your Lord and Savior -- in EVERYthing? With EVERYone? If not, this is where a renewed covenant is needed.
We restore our relationship with God in the ark of the Sacrament of Reconciliation. Because it's a sacrament, Jesus is truly present there, in the form of a priest, to give us a new rainbow, i.e., the promise of his supernatural help to love and live in holiness.