The Believer's Bible Commentary for both the Old and New Testament is an excellent study companion for Sunday School Lessons It is an excellent source especially for David C. Cook's Sunday School Bible Lesson's Commentary 20014-15 edition and more.
This commentary has been a valuable tool in our small group Bible study. It's easy to read and understand, yet offers rich insights into verses so often glossed over. Although this is not the only commentary I use, it clearly is my favorite.
This is the best single volume commentary on the Bible I have come across in the last ten years. The theology is sound and for early believers it is an invaluable resource. The comments are more thorough than one might expect for a single volume commentary. In addition, it incorporates a laymen vernacular understandable to all.