What is sin? It is the glory of God not honored. The holiness of God not reverenced. The greatness of God not admired. The power of God not praised. The truth of God not sought. The wisdom of God not esteemed. The beauty of God not treasured. The goodness of God not savored. The faithfulness of God not trusted. The commandments of God not obeyed. The justice of God not respected. The wrath of God not feared. The grace of God not cherished. The presence of God not prized. The person of God not loved. That is sin.
John PiperA saving knowledge of Christ crucified and risen is not the mere result of right reasoning about historical facts. It is the result of spiritual illumination to see those facts for what they really are: a revelation of the truth and glory of God in the face of Christ-who is the same yesterday today and forever.
John PiperIf we have no zeal for the glory of God our mercy must be superficial, man-centred human improvement with no eternal significance. And if our zeal for the glory of God is not a revelling in his mercy, than our so-called zeal, in spite of all its protests, is our of touch with God and hypocritical.
John Piper