The doctrine of Sola Scriptura (Scripture alone) means that the food that is to feed our souls is to be the Word of God only. You may notice that there is much Scripture in our worship service and when the time to listen to the sermon arrives, the Word of God is usually presented verse by verse from whole books of the Bible. Occasionally there will be a topical sermon, but the general diet of our family's spiritual feeding time is expositional preaching and teaching. There is many reason for this. Timothy Witmer lists ten reasons for preaching verse by verse through books of the Bible in his book, The Shepherd Leader:

1. It identifies exactly what is the heart of the Christian message. (The sheep need the food the Good Shepherd gives in the inspired Word.)
2. It requires that the shepherd concern himself with the intent of the Divine author for every text. (God had a purpose for each part of Scripture.)
3. It respects the integrity of the textual units given through the inspiration of the Holy Spirit. (Teach each books as it was meant to be taught rather than chopping it up.)
4. It keeps the pastor from riding his favorite hobby horses. (Provides a balanced diet.)
5. It challenges the pastor to preach through the "difficult" or obscure texts and "challenging" truths of the Bible. (Christians need to learn how to think through passages that people like to avoid.)
6. Expository preaching will encourage both pastor and congregation alike to become students of the Bible. (Working through books of the Bible helps to know what to look for and how to apply the Word in our on lives.)
7. Expository preaching gives us boldness in preaching, for we are not expounding our own fallible views but the Word of God. (God's promises are linked to His Word and not our 'wisdom.')
8. It gives confidence to the listener that what he is hearing is not the opinion of man but the Word of God. (God has spoken. Our job is to declare what God has said.)
9. It is of great assistance in sermon planning. (Breaking down the book into connected units of thought takes a lot of pressure off of planning a series.)
10. It provides the context for a long tenure in a particular place. (It takes a long time to preach through the whole counsel of God.)