Ephesians is a book about knowing God. (Eph 3:17-19) As Paul puts it, the purpose of his preaching and apostleship is that Christ may dwell in our hearts, that we may know the breadth and length and height and depth [of God and Christ], to know the love of Christ, and to be filled with all the fullness of God. Similarly, the phrase, “In Christ”, occurs 57 times throughout the book. So Paul’s focus is for us to be In Christ, and also to be filled with Christ and God.
Even the demons know about God–James 2–but instead of loving Him, they shudder. Satan must see the love of Christ towards His elect, but reviles it. Then, is seeing the love of Christ towards others enough to know it in Paul’s sense? Obviously not. You’ve got to experience that love, to have the fullness of God filling you.
One of the first times the word “know” is used in scripture is when Adam “knew” his wife Eve, and they had a son. And indeed, knowledge is a frequent term of close relationship throughout scripture. Later in Ephesians, Paul even associates the relationship of husband to wife with the relationship of Christ and His Church. Marriage is a deep, intimate, personal relationship, not just an intellectual understanding.
So then, we must be careful when studying God that we don’t simply learn about Christ, but that we learn Christ. Firsthand experience, not intellectual knowledge.
And this is eternal life, that they know you the only true God, and Jesus Christ whom you have sent. – John 17:3