Although a much shorter and simpler explanation about why Sunday is the christian day of worship can be found in the Scriptures, while reading parts of this book I have learned even more interesting evidence that proves that.
A concise article about what the church is.
Two good articles about why the Faith Only doctrine is in conflict with the Scriptures:
About baptism not being essential for salvation. The first link in this article has the famous argument of 'what about the thief on the cross?'
This article talks about the 'name' of His church, what should it be and why it matters.
About the use of instruments in worship.
These are just a few topics I have been discussing about lately with different friends. I hope they profit you if you wish to know more about them and that you do contrast what they say with your Bible.