I found this prayer from Voltaire's Traite sur la Tolerance last night while doing some research for a paper on religious tolerance:
Make us help each other bear the burden of our difficult and transient lives. May the small differences between the clothes that cover our weak bodies, between all our inadequate languages, all our petty customs, all our imperfect laws, all our foolish opinions, between all of the circumstances that seem so enormous in our eyes but so equal in Thine - may all these small nuances that distinguish the atoms we call men not serve as a basis for hatred and persecution. May those who light candles at noon to celebrate Thee also sustain those who are fully satisfied with the light of Thy sun. May those who show their love for Thee by wearing white cloth not detest those who express their love for Thee by wearing black wool.