Why is the completeness of Scripture important for Christians?

The doctrine of the completeness of Scripture is vital in Reformed theology because it underscores that God has provided His people with a complete and authoritative source for understanding His will and purposes. The apostles were called and equipped by God to lay the foundation of our faith and finish the canon of Scripture, as stated in Ephesians 2:20. This means that the teachings and writings of the apostles, inspired by the Holy Spirit, serve as the ultimate guidance for Christians. With the completion of the Bible, there is no need for further revelation or additional signs, establishing that believers must rely on Holy Scripture as their sole authority in all matters of faith and conduct.