There are so many wonderful things in this short section. Perhaps we have read through this too often and missed its riches. One scholar believes it is a beautiful poetic structure called a "Chiasm." Whether or not the Apostle John intended this isn't clear but we can certainly see the beauty of the structure of this passage in this Chiasm. Check out this diagram of the chiastic structure:
Looking forward to learning together from this fantastic section of God's word!