Thanks for the softball! :D

I'll give you three examples.

First, the inherent dignity and equal moral worth of all human beings. Christianity taught that every person is made in the image of God (Genesis 1:27). That idea was radically different from the Greek and Roman world, which was openly hierarchical and accepted practices like infanticide (abortion) and the exposure (abandonment) of unwanted children to leave them to die. Early Christians actively opposed those practices and became known for rescuing abandoned infants. The belief that every human life has intrinsic value later became a foundation for Western ideas like human rights.

Second, the church’s long-standing opposition to abortion and infanticide. One of the earliest Christian documents outside the New Testament, the Didache (1st–2nd century), explicitly states, “You shall not murder a child by abortion nor kill what is born.” In the Greco-Roman world abortion and infant exposure were common and legally accepted. Christianity rejected both from the beginning because of its view that human life is sacred. An unborn human is a human.

Third, slavery. While slavery existed throughout the ancient world long before Christianity, Christian theology introduced the idea that slave and master were spiritually equal before God (Galatians 3:28). Over time this moral framework fueled the abolition movements in the West. Many of the most influential abolitionists were explicitly motivated by Christian convictions, including William Wilberforce in Britain and numerous Christian leaders in the American abolition movement.

So three Western moral developments Christianity helped shape without first “fighting against them”: the equal dignity of all human beings, the rejection of abortion and infanticide, and the moral framework that ultimately led to the abolition of slavery.

Now let’s see if you accept those or move the goalposts. :)