And he went and began to proclaim in Decapolis what great things Jesus had done for him, and everyone was amazed.
That man obeyed. He went and bore witness. His preaching was not a great theological truth set out in a systematic way, but the living testimony of his personal experience. He told what great things Jesus had done for him. This is the foundation of true testimony. When a person tastes the Lord’s mercy, what God has done in his life naturally sounds from his lips. Decapolis was a region of many cities, and there this man’s testimony became a preparation for the later spread of the Gospel. People were amazed, because his life itself was undeniable proof. He was the man whom everyone knew by his former condition. Now everyone saw his change. Thus, one of the strongest proofs of grace is the new life, which is seen much more clearly against the backdrop of former darkness.