Peter Mead over at Biblical Preaching has what is a very important post on the use of commentaries; not necessarily their use, but their misuse. Like children of old, they should be seen, but not heard. He asks:
I wonder whether the commentaries have been conversation partners in the personal study of the text, or crutches leant on to short-cut the process of exegesis. I wonder whether the commentaries have simulated wrestling with the structure and flow of the text and consequently the sermon, or whether they have merely furnished a dissected structure on which to hang the broken pieces of a partial sermon.
Find the whole post here.