The NewCity Orlando All of Life Podcast 1-3 John | CBR Bible Introduction Project
A helpful resource for 1-3 John is the ESV Gospel Transformation Study Bible. It is like a regular study Bible, except that the study notes are focused on understanding and applying the text to our personal lives. And, this resource would be useful for all the books we read in CBR as well.
For 1-3 John specifically, Ben recommends Studies in 1 John by Martyn Lloyd-Jones. The Letters of John by John Stott in the Tyndale New Testament Commentary series is an easy to read commentary. That entire commentary series is a good place to start for interested readers.
Another resource for interested readers is A Biblical-Theological Introduction to the New Testament: The Gospel Realized. In it, readers will find chapters devoted to more extensive issues related to interpreting books of the Bible. There is a companion volume covering the Old Testament, and both are worth the investment.