QUESTION: Why do some churches preach out of the Old Testament when we are living in New Testament times under grace?
ANSWER: Even though we are ‘living in the New Testament’ the Bible clearly tells us that all Scripture has been given by God and is profitable to us (2 Tim 3:16). How so? First of all even the Old Testament Law, when used ‘lawfully’ the Bible says acts like a schoolmaster to lead us to Christ and ultimately justification by faith (Gal 3:24). Without the Law there would be no conviction, without conviction there would be no repentance, without repentance there is no salvation. Once saved, both the books of Galatians and Romans clearly teach that we are no longer under the Law. But the Old Testament still has value.
Take the time to read 1 Corinthians chapter ten. No one can deny that the writer of this book (Paul) was a preacher of grace. Notice, however, that in the entire chapter he uses Old Testament Scripture and incidents as examples (v.6 and again in v.11). 1 Corinthians 9:9-10 as well as many other New Testament passages do the same thing.
Praise God that we are not living under the Law today! However, the Old Testament still has much value when it is rightly divided. Old Testament principles that are repeated in the New Testament apply to us today and in teaching those principles we can look back to the Old Testament to help learn the lesson. Christians don’t observe the Sabbath (Saturday) or offer animal sacrifices because those commands are no where repeated in the New Testament.
Think about it…when Jesus preached (not to mention the first century church), every Bible verse He quoted was from the Old Testament!