Christianity set itself the goal of fulfilling man's unattainable desires, but for that very reason ignored his attainable desires. By promising man eternal life, it deprived him of temporal life, by teaching him to trust in God's help it took away his trust in his own powers; by giving him faith in a better life in heaven, it destroyed his faith in a better life on earth and his striving to attain such a life. Christianity gave man what his imagination desires, but for that very reason failed to give him what he really and truly desires.

Lecture XXX, Atheism alone a Positive View - Lectures on the Essence of Religion (1851)