Moses warned Israel that even if a prophet or dreamer gives a sign that comes true, the people must not listen to his voice if he calls them to worship other gods, because the Lord is testing whether they love Him with all their heart and soul (Deuteronomy 13:1-3). That warning stands behind the ancient Shema, “Hear, O Israel, the Lord our God, the Lord is one” (Deuteronomy 6:4), the confession Jesus Himself named as the greatest commandment when asked which commandment is first of all (Mark 12:28-31).
Because so many voices compete for God’s people, testing every claim against His revealed Word rather than against signs and wonders is essential, and the service moved from that warning into the church’s own response: renewing the Lord’s Supper and reciting a shared confession of faith, declaring belief in God the Father Almighty, in Jesus Christ who rose again and is Lord, and in the Holy Spirit who conceived Christ the Savior.