"But Peter kept on knocking and when they opened the door and saw him, they were astonished. Peter motioned with his hand for them to be quiet and described how the Lord had brought him out of prison. 'Tell James and the brothers about this,' he said, and then he left for another place." NIV translation
What a lesson we have here in that, when God is at work in your life, you should tell others about it. After being rescued from prison and the death penalty, all Peter asks of those that were gathered is for them to tell others of what God had done. As Christians, that should be us every day as well as we see God at work in our lives. Maybe it is not God rescuing us from prison every day but, if we are watching we will see God at work in our daily lives and every day is an opportunity to tell others about what God is doing.
"In the morning, there was no small commotion among the soldiers as to what had become of Peter. After Herod had a thorough search made for him and did not find him, he cross-examined the guards and ordered that they be executed. Then Herod went from Judea to Caesarea and stayed there a while." NIV translation
It seems that Herod was always at odds with God's plan. At Jesus' birth, he had the little children killed because he couldn't find Jesus and now he has the guards killed because he can't find Peter. You would think that maybe he would stop and realize that something bigger than himself is going on but he doesn't. The same can probably be said of us at times as God is at work and we don't take notice and we may even get frustrated, like Herod, and do bad things. That is why we must be always in prayer and looking for God at work in our lives.
"He had been quarreling with the people of Tyre and Sidon; they now joined together and sought an audience with him. Having secured the support of Blastus, a trusted personal servant of the king, they asked for peace, because they depended on the king's country for their food supply. On the appointed day Herod, wearing his royal robes, sat on his throne and delivered a public address to the people. They shouted, 'This is the voice of a god, not of a man.' Immediately, because Herod did not give praise to God, an angel of the Lord struck him down, and he was eaten by worms and died." NIV translation
Things must have been looking pretty good for Herod as he had killed some of the disciples and then some of his enemies came to him to ask for peace. He gave a big speech and the crowd loved it and even lifted him up as a god. But, God is a jealous god and does not share his position with anyone and so Herod was killed by an angel of the Lord. We all probably know of someone that is openly hostile to Jesus Christ but it seems like they are still prospering in the world. This passage can serve to remind us that God is in control and he will take care of those who elevate themselves to God's throne.
"But the word of God continued to increase and spread. When Barnabas and Saul had finished their mission, they returned from Jerusalem, taking with them John, also called Mark." NIV translation
No matter what rulers tried to do or the people they arrested, God's word spread. That was true then and it is also true today as there are many countries where the leaders try to keep the people from hearing the gospel but God is still in control and working there.