In this chapter, I think that Packer wants to make the point clear that our image of God can often become twisted and perhaps even blasphemous. I think we often do conjure up images of how we feel God should be like. We tend to emphasize the characteristics of God that we enjoy or at least don’t mind, may it be His love, kindness, and gentleness. On the other hand, we try to minimize the characteristics of God which we find “inconvenient” such as His holiness and justice. In the Bible, we see that the Israelites often loved God when he was merciful (e.g. salvation from oppression) or when He proved providential (e.g. blessing their crops). However, when it comes time for them to obey God’s commands and keep their commitment to be His holy people, they often forget God altogether and went on to worship idols.
In much the same way, we feel spiritually high and close to God when we feel His presence after He has blessed us in some way. Conversely, when we are faced with trials in life, we often either grumble against God or forget Him as being sovereign over everything. I believe that Packer is trying to emphasize that when we begin studying God and who He is, we should be ready to accept every aspect of Him and understand that knowing Him involves embracing Him totally.