A Bible commentary is a series of notes explaining the meaning of passages of Scripture. A commentary may explain the language used in a section of text. Or it may discuss the historical background. Almost all commentaries attempt to explain the passage in terms of some system of theology. In other words, the commentary is an explanation of how the Bible fits together and what it means. Since a Bible commentary is written by human authors, it will reflect the beliefs and perspective of those writers.
Some Bible commentaries are arranged like a book, with long sections of text. Others are arranged like an outline, where each individual section is distinct from the rest. A few Bible commentaries are centered on some particular theme. Some study Bibles, such as the John MacArthur Study Bible or the Ryrie Study Bible, come with extensive notes; such editions of the Bible are essentially a commentary printed side-by-side with the text.
Commentaries are widely used in personal Bible study. The advantage of a Bible commentary is that one can quickly gain perspective on the text’s meaning, as understood by the commentary’s author. One caution concerning Bible commentaries is that they should not be used instead of personal study; rather, they are designed for use in addition to personal study. Since the commentary itself is not Scripture, it’s important for a reader to weigh what he reads against other sources, as well as his own Spirit-led analysis. As the products of fallible people, commentaries are not necessarily correct in every word.
Got Questions Ministries is in the process of building a comprehensive, free, searchable online Bible commentary. You can find this at www.BibleRef.com. The emphasis of BibleRef is context: the importance of understanding each verse of the Bible in terms of its overall setting, related verses, history, and so forth.