The prayer, "Lord, concern yourself with your servants," is an interesting appeal. They ascribe magnificent sovereignty to God in their prayer. This (Acts 4:28) and Acts 2:22-24 are overwhelming -- that God would purpose to and then deliver Jesus to death. They trusted him because they knew the Scriptures. Both Acts 2 and Acts 4 are saturated with key O.T. promises.
The result of being in the hand of a God like that is deliverance, faith and community, a community full of faith and of one mind. Of course, the earthquake is cool, too.
The "everything in common" part of the church seems to good to be true. And, in chapter 5 we find that it is. There must be a governing by the Holy Spirit, not just on the leaders, but on everyone, if the congregation is to function that way.