What does Romans 15:4 mean?
Paul seems to take a bit of a detour from his main point with these words. In the previous verse, he quoted from Psalm 69 to support the idea that because Christ did not please Himself in this life, self-gratification should not be the main priority of Christ-followers.Now Paul seems to comment on his practice—seen in Romans and throughout his other letters—of quoting Scripture to support his teaching about Christ. For the modern reader, Paul's references are from what we now call the Old Testament. It is true that Christians have died to the law in Christ and have been released from any obligation to obey the requirements of the law (Romans 7:4–6). That does not mean, however, that the scriptures from the "former days" have stopped being valuable.
Paul insists that those older Scriptures were written to teach modern Christians, not just those who read them in the former times. Those Scriptures are for us, too, to bring encouragement and hope to God's people in every generation. They help us to endure, even in and through suffering.
This verse serves as an answer to modern Christians who ask, why even bother to read the Old Testament? Regardless of age, those writings remain the revelation of the heart of God. The fact that we have been freed in Christ from following the law does not stop those 39 books from being the Word of God, full of truth, wisdom, history, and great encouragement for believers. Paul insists that we place value on those Scriptures and seek out encouragement and hope from them.