This article compares Euripides’s Iphigenia Taurica with Goethe’s Iphigenie auf Tauris, and investigates how the theme of love between siblings is related to the religious issue in both tragedies. I firstly analyze how, in the Euripidean tragedy, the value of familial love can connect the two worlds of gods and humans, thanks to the parallel between the human (Iphigenia and Orestes) and the divine couple of siblings (Artemis and Apollo). By sharing this human value, the gods demonstrate that they can be different from the immoral deities depicted in myth, and correspond to Iphigenia’s ethically purified image of them. However, the Euripidean plot included at least three elements which an Eighteenth-century intellectual could not accept (paragraph three): the obscurity of the divine messages; the centrality of theft and cunning; the inability of men to solve the tragic predicament autonomously. The value of family affection is momentous for the removal of those elements (paragraph four): in the Goethean play, the Gods demonstrate that they share it not by directly intervening, but by providing the human sister with the powers of the divine sister: therefore, Iphigenia can heal her brother, and the statue of Artemis need not to be stolen. Iphigenia proves that the gods speak to the human heart, and in this way the problem of communication with the supernatural sphere is solved.