First book of john goes into depth about the living expression to of God the church which is in Christ being among as and dying for us giving the church instruction on how they should conduct themselves. The second letter is how they should live in truth and not to fall for false teachers and what to notice. The 3rd is a letter about stay on the path of truth which is really could of been added to the 2nd letter but also adding on how they should be hospitable.
