Gotthold Ephraim Lessing's (1729 – 1781) play, Nathan the Wise, was published in 1779 but immediately condemned by the Church. It was first performed in 1783 and was considered highly controversial in its treatment of religion. It is a plea for religious tolerance. The eponymous character, Nathan, was based on Moses Mendelssohn (1729- 1786), a German Jewish professor who was a close friend of Lessing's.
The play is set in Jerusalem during the Third Crusade. This was a period that marked direct conflicts and interactions between Jews, Muslims, and Christians, who all revered Jerusalem as a holy site. Lessing in this play is arguing that as all the Abrahamic religions spring from the same root, they are all, as it were, offspring of the same God, who stands as a parent to all three.
The key metaphor he uses is the parable of the three rings given by a father to his three sons, whom he loves equally. The father makes three identical copies of the ring, so that no son can actually know if he is the heir. Thus each son is encouraged to behave as best as he can to show himself worthy of the inheritance. Nathan says that the three Abrahamic religions are like this, all equally beloved of God, their father, and none able to prove itself more authentic than the others. He emphasizes that it is an act of false pride to find only one's own tradition worthy of respect:
The worst of superstitions is to think
One's own most bearable.
The Sultan echoes this point of view in the following critique of Christianity:
Their pride is to be Christians, never men ;
Ay, even that which since their Founder's time
Hath tinged their superstition with a touch
Of pure humanity, is prized by them
Never because 'tis human, but because
'Twas preached and practised by their Jesus
In other words, the point is that doing good and human deeds are what make a religion good, rather than the deeds being justified by the name of the God in whose honor they are done. The final plot twist, in which the true identities of the young lovers are revealed, proves that the accident of one's ancestry is less important than how one lives one's life.