Sermon preparation is not poker, so let me show you my hand.  I pull from many different resources as I am preparing for Sunday morning, and they fall into the categories of "look and listen:" books, commentaries, sermon manuscripts and sermon audio.  Those I am currently using for our study of Exodus are (in no particular order):

• John Frame's lectures on Ethics, which springboard off of the 10 Commandments.  These have been recently released in book form, but are also available online as Doctrine of the Christian Life.
• Bruce Waltke's excellent book, Old Testament Theology, recently released and compiled from his years of faithful teaching of the OT.
• Douglas Stuart's commentary on Exodus in the New American Commentary series.
• Peter Enns' commentary on Exodus in the NIV Application Commentary series.
• Philip Ryken's sermons from his preaching of Exodus at 10th Presbyterian in Philadelphia, PA (Ryken was brought on as pastor after James Boice's death.)  These are printed in the book Exodus: Saved for God's Glory, from the Preaching the Word series.
• Ligon Duncan's sermons from 1st Presbyterian in Jackson, MS.
• John Piper's sermons from Bethlehem Baptist in Minneapolis, MN, found at desiringgod.org
• Ray Stedman's sermons, if he speaks on the subject.
• Other articles and sermons from past and present mighty men of God, usually found by searching at monergism.com