There are many reasons to own good, Bible-saturated, Gospel-centered books. One of the least-obvious reasons is that they will preach to you about your sin and the sufficency of Christ from the shelf. Often, you don't even have to read them to benefit from their preaching.
Here's what I mean: I cannot count the times that I have simply scanned my shelves and focused on a particular book. God uses the title or content of that book to encourage, challenge, or rebuke me. Let me give you a few examples:
1. Chapell's "Christ-Centered Preaching" challenges me think deeply about my sermons and if Christ is central in my preaching. I have only read a few sections of that book. However, its mere presence on my shelf has been used of God.
2. Scott's "The Exemplary Husband" often reminds me to love and care for my wife. Whenever I see the title, a question immediately comes to mind: "Justin, are you an exemplary husband?"
3. Wells' "Above All Earthly Pow'rs" sits directly across from my desk as the very last book on the shelf that is just lower than eye-level from where I sit. I see it often. It spurs me to worship Christ when I see it. It reminds me that Jesus Christ is the sovereign Lord of history and that one day every knee will bow to His authority.
These counselors are gifts of God's grace to me every day.
Let me give one last, very personal, example from last week. This example is what prompted my thinking on this gift of grace.
God graciously led me to repentance last week through the mere presence of these biographies on my shelf. As you can see, they have very colorful dust jackets. When I look at my biography section, they immediately stand out.
I had been sinning by wasting precious time that had been given to me as a gift to be redeemed for Christ (Eph. 5:16). I was justifying my sin by reasoning that "everyone needs a little recreation and time to take it easy."
I just recieved these biographies as a gift from a generous friend. They have only been on my shelf for a few months (at most). There they sat, rebuking me. They said, "Justin, remember all the godly men who have recommended these 2 volumes as among the most influential biographies they have ever read? Why don't you pick us up and read us?" My answer: "I don't have time right now. I am busy and am reading other things." They gently replied, "What about that time that you call recreation? You could have read at least one of us in this past month if you had maximized your time."
God used that conversation in my conscience to preach the gospel to me. I was reminded that I am still in need of a Savior. God is good to lead me to repentance using unlikely sources: the mere presence of good books. How many countless times has he used the acutal content of these books? Myriads!