“My thoughts are not your thoughts, neither are your ways my ways”—is often quoted when we face something we don’t understand, like suffering, unanswered prayer, or the mysteries of God’s nature. People use it to say, “God is incomprehensible, and his ways are simply beyond us,” especially in moments of pain. Yet in Isaiah 55, these famous verses sit inside a sweeping altar call—a global invitation from God himself, calling sinners to turn from their wicked ways and unrighteous thoughts and to receive his abundant pardon. In this message, we Think Again about Isaiah 55:8–9 and see that God isn’t merely reminding us of his mystery; he is contrasting our sinful ways with his gracious ways and urging us to repent and come to him. Isaiah 55 presents four parts of God’s altar call: the grace of Christ’s offer, the urgency of his call, the description of a right response, and the promise of his saving work in those who believe.