You might think a preacher marks up his Bible more than anyone else with highlights, underlining, references, definitions, etc. I used to be of that mindset. I thought it ideal, for example, if I were teaching a class on Matthew, if I could just open my Bible and have all my study notes in microscopic print in the margin. That way, no additional notes or notebook would be necessary to teach the class; I could carry my Bible and nothing more (how marvelously simple!). Over time, my Bible-marking ways evolved into anti-marking. I didn’t just decide to mark less in my Bible; I ceased it altogether (writing on the blank pages in back of the Bible doesn’t count). Here’s my reasoning, and you may feel free to differ in public or private, and to offer constructive or abusive criticism.
First, margin notes are not easily transferred. Any continuously used Bible will wear out and, no matter how precious your handwritten margin notes, the day will come when you have to replace your Bible. Transferring notes then becomes a daunting or even impossible task, depending on their copiousness (not to mention legibility).
Second, writing in your Bible is a constant battle against the margin (usually a small margin). Bibles I tend to favor are diminutive in size. I don’t want lengthy book introductions, extensive outlines, commentator’s notes across half the page, archaeological supplements, or a hefty concordance in the back. All of that makes for extra pages I have to carry around. If I need a concordance, I’ve got a better one on my bookshelf and even online than one in the back of a study Bible. All I need in a Bible are a few maps (optional), some handy cross-references (if a study Bible), and footnotes (esp. translator’s textual notes). In other words, I want a Bible that fits my hand–not a backpack–and that usually means one with small margins which are not conducive to handwritten notes.
Third, marking your Bible brings the danger of impairing the readability of the back side of the page. Without just the write kind of pen, handwritten notes tend to bleed through thin Bible paper. There are colored pencil options, but I believe in ink (pencils are for elementary school). So, your eloquent comments regarding Matthew 6:33 (on page 7) end up bleeding through to page 8 and making the “Golden Rule” (Matt. 7:12) unreadable. Not good.
Fourth, margin notes anchor you in yesterday’s level of understanding. I’m not going to teach a Bible book exactly the same next time around. My understanding grows with time and learning. Points I may have highlighted years ago may be superceded by more apropos material now that I know more. But, where am I going to put additional notes from further fruitful study if my margins are already full from what I wrote ten years ago? Maybe my first tour through the book was mediocre and now I’ve got a Bible full of mediocre notes that leave no room for more meaty reminders. Maybe, instead of margin notes, you underline verses, but, over time, discover that you wish you had not underlined a verse (like Gen. 1:1). When I was about twelve, my grandfather gave me an expensive Dickson Analytical Study Bible. It had a moroccan leather cover and more study helps than you could shake a stick at. Were I still using that, you can believe that the underlinings (etc.) I put in it back then are not what I would have put today.
Fifth, Bible-marking creates the risk of missing something important. To me, this is the weightiest reason of all. If you underline a verse (or highlight it in a color, or notate the margin), then your eye is drawn to that verse every time you open the Bible to that page, right? It’s as though we’re saying that verse is super-important, as opposed to the rest of the verses on the page, which are not important enough to merit highlighting. With the subconscious emphasis drawn to the highlighted verse, what becomes of my ability to notice the verses right before, or after, the highlighted verse? What if I unintentionally treat the highlighted verse in the second column as more significant than anything in the first column? When I look at a Bible page, I want it to contain God’s words instead of my own, for my own may serve to detract from my ability to fully appreciate God’s.
Now, as the saying goes, your mileage may vary. You may benefit greatly from marking up your Bible. If so, more power to you. There’s nothing wrong, either way. These are simply my own opinions, and I’ve never seen anyone enumerate the view I’ve grown to adopt.