This article demonstrates how Cranach the Elder's Schneeberg Altarpiece of 1539, the first evangelical retable, instructs viewers in Lutheran theology and actively perpetuates evangelical public devotional practice. The strategies of the retable s iconography, which derive from Luther's sermons and other writings, explicate Luther's notion of justification by grace through faith. This model of salvation creates a new foundation for the pictorial interpretation of traditional subjects. The Schneeberg Altarpiece establishes a discrete phase of evangelical painting, still bound by devotional forms of late medieval Northern art (the retable) yet departing from the insistent didacticism of the earliest evangelical images known as Law and Gospel. Earlier scholarship has tended to focus on iconography, rendering the Schneeberg Altarpiece secondary to the theology it embodies. This article contends that the Schneeberg Altarpiece actively changes the purpose of religious art.