How do we know that Christ's sufficiency is true?

The sufficiency of Christ can be confirmed through the miracles He performed, which serve as testimonies of His divine power and ability to provide. For instance, in John 6, the miraculous feeding of the 5,000 illustrates how Christ meets needs that appear impossible to fulfill with available resources. Additionally, the truth of His sufficiency is supported by Old Testament prophecies that reveal His readiness to provide for His people. The sufficiency of Christ is authentically seen in the New Covenant, where He declares through His work on the cross that it is finished—demonstrating that there remains nothing we can add to our salvation.