This may take most people by surprise, but Preaching is one of the most difficult things you can do. It looks easy. All you have to do is stand up, talk about the Bible and then your work is over for the week! If only it were that easy. Even apart from the weight of its importance, it is terribly difficult. Part of it's difficulty is that it is deceptive. It looks easy, but it's anything but. It is both an art and a science. There are certain elements that we can learn in the classroom and others that we can't.
If I had to narrow it down to one particular temptation that I face - and that I believe many others face - it would be assumption. Those who have theological education like myself can approach a passage of Scripture and assume that we already know what it means. Familiarity with certain books or passages can lull us into a false sense of security and understanding. It's easy to identify a sermon that was build on assumption: it has a certain flatness to it. It can be propped up with all kinds of big words and appeals to ancient languages, but you can't fake depth.
When we assume that we understand a text we are robbing ourselves of the opportunity to sit with the text and see the layers unfold. The longer we meditate on a passage the more we begin to see; the more it penetrates our hearts. The famous preacher G. Campbell Morgan would read a book of a Bible at least fifty times before he would ever begin his sermon preparation! Fifty! If I read a passage five times before sermon prep I'm feeling good. But, that familiarity shows up in the pulpit. It creates a depth and compassion that cannot be faked.
Even if you're not a preacher, take some time to read a whole book of the Bible in one sitting. You can start with a short one - try Jude, Philemon or Habakkuk. Read it all the way through without stopping. Then, read it again; and again; and again. Read it until you can't imagine seeing anything you haven't already seen before, then read it again. The more you read it the more the Lord will begin to show you those deeper riches.
What will surprise you - and what will transform a pastor's preaching - is that depth does not equal complicated. Depth is often simple, yet profound. Sometimes it may be complex or difficult, but it will never be convoluted or asinine. The next time you go to read your Bible try reading the same passage repeatedly. Be careful you don't fall into the trap of assumption. You know what happens when we assume...