What is the main conflict in The Grand Inquisitor by Fyodor Dostoevsky?

The legend of the Grand Inquisitor is a story within a story. Jesus returns to Earth during the Spanish Inquisition and is arrested. The Grand Inquisitor visits him in his cell to tell him that he is no longer needed on Earth. The Church, which is now allied with the Devil, is better able than Jesus to give people what they need. The story has often been considered a statement of Dostoevsky's own doubts, which he wrestled with throughout his life.