How do we know the doctrine of common faith is true?

The truth of the doctrine of common faith is established through various New Testament scriptures. In Titus 1:4, Paul refers to Titus as his son 'in the common faith,' highlighting the importance of this unity in belief among believers. Furthermore, Ephesians 4:4-6 emphasizes that all believers share in one faith and one calling, attributing this unity to the working of the Spirit among God's people. This common perception of faith as a gift from God reinforces that the truths of the Gospel are consistent and shared among the elect, making the doctrine true and significant for the Christian life.