Exodus 12 contains the heart and soul of Judaism and therefore of Christianity: Passover. God had to decide what to do with humans who choose to sin. His Grand Solutions was the Passover; not the Exodus version, but the Jesus version.
God decided to personally intercede with sin and destroy it Himself. As the Gospel of John has it, Jesus was dying on a cross outside the city at the very time thousands of Passover lambs died inside the Temple.
In Exodus God instructed the people to mark themselves with the blood of the lamb. We who follow Jesus are marked with the Blood of the Lamb by the Holy Spirit so that the Wrath of God will pass over us with his Sword of Justice; not because we have not sinned but because God has called us to be his and has promised not to kill us.
But I still sin. Living in a world of sin is like living in Seattle, I will get wet. Sin happens. We deal with it the way Paul instructed, that is, to love. It is the same message Jesus gave: love others as yourself and love God. Easy, and so hard.
Jesus gives us another way to deal with the sins of his followers, to help each other. The reading for today must be taken in context with all of chapter 18. He who has wandered away needs to be rescued; the lost sheep. We do not deal with him like the unmerciful servant, we seek to encourage, to help, to build up.
The words of Jesus in Matthew are not intended as a format for churches to follow, but as an example for you and me to follow. The whole church need not be bothered with most of our sins. For example: If I hear someone say, “That boy in the White House…,” I should first try to understand what the person meant by using the diminutive, boy. Perhaps he calls everyone boy, like a waitress calling everyone Hon. In that case I could suggest, “You might want to choose a better term for this President.”
Life is full of these little sins. Guard against them. Think about what you say and what you mean. Is it hurtful? Does it demean someone else? At the same time we cannot go on the warpath over these kinds of sins. I learned early on that we have to pick our battles. Anyone who has ever been an official in any sport knows that rules are broken in nearly every play, even among the professionals. My father bragged that in high school basketball, he was never caught holding the shorts of the guy in front of him trying to rebound the ball.
We need to call the ones that cause the most harm and pray for the wisdom to know the difference.
Be righteous and do good.