Some people would like to apply this line of thinking to God (and more to His relationship with Jesus). Just the other day my 3-year-old son asked me who made God. And so in this chapter Lewis attempts to explain the nature of the relationship between the Father and Son, in so far as their relationship to each other goes (remember, in a previous chapter Lewis went to great lengths to explain how God created humanity, but begat Jesus). I feel that Lewis does a fantastic job explaining how it is possible for the Father and the Son to have always existed, and how there was never a time before God produced the Son.
I was also bowled over when Lewis talked about our notion that we like to throw around that “God is love.” This is true, but it would be impossible without God being trinitarian (yup, WordPress spellcheck tells me that “trinitarian” is not a word. Of course, it also tells me that “WordPress” is not a word). If He was merely one person He could not possibly be love. Take a couple of minutes to read it for yourself. There is also some very intriguing work with the role of the Holy Spirit in this chapter that will make you wrestle a little bit.
In summary, a great chapter that made me wrestle with how I view some of the ways I have been looking at the nature of God lately.