“#3 AVOID COMMENTARIES”
“Commentaries can be useful tools, but they can be deadening for preachers. Spend more time in the biblical text and thinking for yourself about it, and less time answering the problems of the commentators. Scholars who write commentaries are talking to each other, answering each others’ questions. They are not the questions that the person in the pew has, and they’re often not what the text is about either. Even the best, biblical commentators still have to answer many questions entirely irrelevant to the people you are serving on a Sunday morning. Knowing the answers to these questions is still important, but you can’t let it take up all your sermon preparation time.”
You can read Phillip Jensen’s whole article here. Very helpful.