According to the prophet Isaiah, the punishment that brought us peace was upon Jesus. Paul states this in Romans, chapter three verses 25 and 26 speaking about the substitutionary death of Jesus:
"God presented him [Jesus] as a sacrifice of atonement, through faith in his blood"
That word ‘sacrifice of atonement' is also used to denote the mercy seat that covered the ark in the tabernacle of Moses. Now that mercy seat was the only place where God appeared to man in the tabernacle and where God could offer man peace where the blood was sprinkled each day, each year. That mercy seat was over the ark, which contained the Ten Commandments, which was the law that the sinner had broken. So the mercy seat was the covering of God's mercy that hid the broken law. But Jesus on the cross became that mercy seat, that sacrifice of atonement, through faith in his blood. And then he goes on to say:
"He [God] did this to demonstrate his justice, because in his forbearance he had left the sins committed beforehand unpunished ‑ he did it to demonstrate his justice at the present time, so as to be just and the one who justifies the man who has faith in Jesus." (NIV)
So God had this problem, he had passed over sin in past generations where there had been true repentance, but the sin had never been finally dealt with. It was God's forbearance, it was his longsuffering. The sacrifices that were offered under the Old Covenant could not finally take away sin. But in them, there was a remembrance of sins every year and each Day of Atonement for the Jewish people. Their sins were covered for one more year, but never finally dealt with. The only way that sin could finally be dealt with was by the substitutionary sacrifice of Jesus on the cross where God demonstrated his justice. He demonstrated his total uncompromising hatred for sin even in the person of his beloved Son, but at the same time, having demonstrated his justice, he made the way open to offer his pardon, his forgiveness, his peace.
Thank You, Jesus, that You are my Mercy Seat, that You not only just cover my sin, but that You have totally washed it away with Your precious blood. Help me, Lord, to hate sin uncompromisingly, just as You, and help, through faith, to also uncompromisingly believe in the total forgiveness, offered to me through Your sacrifice, and to rejoice in Your Presence, where I now freely may come, in Jesus’ Name, Amen!