Luke 4:40-41 (ESV)
Now when the sun was setting, all those who had any who were sick with various diseases brought them to him, and he laid his hands on every one of them and healed them.  And demons also came out of many, crying, "You are the Son of God!" But he rebuked them and would not allow them to speak, because they knew that he was the Christ.
Now when the sun was setting, that is, when the Sabbath was over. Bo Giertz brings up this point. Everything he has been talking about up to this point has happened during the Sabbath. His preaching and even the healing of Peter’s mother. Now that the sun is setting, the Sabbath is over people are going back to life, doing things again. I never will forget Saturday evening in Jerusalem, it was like someone opened the flood gates. A town that was dead moments before, where few stores of any type were open, and you could barely get a person to tell you where an ATM machine was, burst to life in moments, and became so crowded, you had no choice of where you were going to go. Traffic went in one direction only, on any given street, it was all foot traffic.
The Sabbath is over, the law is no longer holding people back from being healed. There is no salvation in the law. The people could try to keep it until they were blue in the face it would not heal them. But the Sabbath being over, the law gave way to gospel as people were brought to Jesus and healed. Later he will get into much mischief as people realize it is the law, it is the Sabbath that is holding them back. Jesus will heal on the Sabbath in spite of the law. But here, as the light dims, the gospel shines. It is trust in the gospel, faith that heals us from our infirmity, not following the law.