Karl Marx once said, “After all, we can forgive Christianity much because it taught us to love children.” Almost unbelievably, the factual part of that statement is right. Christianity did have such an effect on the Western world. Throughout antiquity, children had been thought to have little or no value. In Rome, fathers had absolute authority over their children: they were legally permitted to kill them for any reason, even on a whim. Infanticides were rife all over the Mediterranean. Children were regularly sold into slavery. I can’t think of any references in classical literature to the value of children. That’s far from true, though, of Buddhist and of Christian literature. From the Gospels on, Christians held children up as an earthly ideal. This attitude has been revealed in Christians’ charitable endeavors throughout the centuries.
More generally, Christianity’s great contribution to Western civilization was the preaching of love. The ideal of love was foreign to Plato, to Aristotle, to the Stoics, the Cynics, the Epicureans; at most, these schools praised virtue. The old classicist W. W. Tarn said it well in his book Hellenistic Civilisation (1927):
"...And of all the Hellenistic creeds, none was based on love of humanity; none had any message for the poor and the wretched, the publican and the sinner. Stoicism came nearest; it did transvaluate some earthly values, and Zeno, at least, gave offense by not repelling the poor and the squalid who came to him; but it had no place for love, and it scarcely met the misery of the world to tell the slave in the mines that if he would only think aright he would be happy. Those who labored and were heavy laden were to welcome a different hope from any which Hellenism could offer."
This is the Christianity that should be honored, the Christianity of St. Francis, of Jesus, and in our own times of liberation theology (which, arguably, was a return to the original essence). Thomas Jefferson thought that the only part of the religion worth keeping was the Sermon on the Mount.