The oldest known records of slavery come from Mesopotamia some five thousand years ago. Then Egypt. Then China. Then the Bible of course, and then Greece and Rome. They continue for many centuries, presenting an ongoing, ubiquitous social institution, cultivated by humans everywhere, trophied by kings, excused by philosophers, meticulously documented by diligent clerks.

Enslaving other humans has been one of the most common and universal of human activities. Indeed most people in the ancient world would have struggled to imagine a human society without slaves, and hardly regarded slavery as an institution that could be separated from society or conceivably be abolished.
It is worth noting that even the nation that founded its national and religious identity on its exodus from slavery – the ancient Israelites of course – held slaves, and did not object in principle to the institute of slavery. The Greeks as well, being the first to introduce democratic principles and institutions to political life, did not reject slavery, and indeed found ample reasons to legitimize it.
Only with the rise of Christianity do we witness the first ever principled objection to slavery. Examining this historical ethical breakthrough will allow us to begin to understand the seminal part that is played by the idea of the creation of all humans in God’s image throughout the history of the West.
Significantly, while slavery in antiquity had certain social and economic logic, any society that enslaves humans needs to legitimize the abhorrent practice ethically. Humans, it seems, have a deep psychological need to justify the injustices that they inflict on other humans.
For the Israelites, it was fairly easy to justify slavery: their laws about slavery were divinely ordained. The Bible, while beginning with the proposition that all of humanity was created in the image of God, also tell of the reasons some are enslaved (the Curse of Ham, Genesis 9), and lays out laws for the regulation of slavery. These laws, among the earliest legal codes addressing the treatment of enslaved individuals, imposed rigorous ethical obligations on slave owners, making Israelite slavery more controlled and humane than any other of the ancient Near Eastern societies.
For these, as for any society that was not based on divine law, ethnicity often provided a basis for racial justifications for slavery. Such was the case with the Spartans, who enslaved the Helots, a name they used for different ethnic groups (Messenians and Laconians) whose members they enslaved for agricultural work and other tasks they considered beneath them.
The assumption was that enslaved ethnic groups were substantively destined for slavery: that their members were not free because they were different in some essential sense and inferior to their masters. This apparently logical resolution was consistent with the teleological disposition of the ancient world: the belief that everything had a function and a purpose, which it had to fulfill. Some people were simply born to be slaves
Teleology was of course the organizing principal of Aristotle’s philosophy, an authoritative voice not only in antiquity but throughout the Middle Ages. For Aristotle, slaves were “living tools” in the hands of their masters, while slavery itself was a natural essence with which one was born: “From the hour of their birth, some are marked out for subjection, others for rule”, he wrote in his Politics, explaining how enslaved humans’ bodies physically differed from those of the free.
Of all Hellenistic thinkers, the Stoics were the most positive in their attitude towards the enslaved, though even they did not reject the institution outright. For them the body-soul dichotomy, central to Greek thought, made slavery tolerable. Since the soul, according to the Stoics, was the locus of true personhood, and since, in their view, the soul was eternally free, there was no way to truly enslave anybody. It was not so terrible, therefore, to enslave humans, as one could subjugate only their bodies.
The fundamental change in relation to the institution of slavery began with Christianity. With its transformation into a major, widespread religion, the idea that all humans were created in the image of God gained acceptance across the Mediterranean Basin and into Europe.
Thus when Constantine began Christianizing the Roman Empire at the dawn of the fourth century, imperial law was shaped by this principle. Eager to express Christian ideals in the legal code, the emperor instituted preliminary protections for such weak sections of society as children, peasants, prisoners, and, of course, slaves. Thus, for example, an edict proclaimed in 316 made it illegal to sear a mark on the face of a convict “because man is made in God’s image.”
The Church did not abolish slavery, and in fact there were many clergymen, as late as the 19th century, who supported slave ownership and used various theological arguments in an attempt to justify their positions. Yet as early as the period of the Church Fathers, in the third and fourth centuries CE, there were pioneering voices of principled opposition to slavery, predicated on the principle of the image of God.
Among them Gregory of Nyssa was the loudest and most explicit in his rejection of slavery. For Gregory the very attempt to buy or sell a human being was inherently absurd:
God said, let us make man in our image, after our likeness. If he is in the likeness of God, and rules the whole earth, and has been granted authority over everything on earth from God, who is his buyer, tell me? Who is his seller? To God alone belongs this power… But has the scrap of paper, and the written contract, and the counting out of obols deceived you into thinking yourself the master of the image of God? What folly! …Your origin is from the same ancestors, your life is of the same kind… Are not the two [slave and master] dust after death? Is there not one judgement for them? A common Kingdom, and a common Gehenna? (Homilies IV, Eccl. 2:7)
Humankind’s creation in God’s image, according to Gregory, not only gave them supreme value but also made them, in the fullest sense of the word, subjects. In this respect, no human could ever be deprived of their personhood and considered an object that could be bought and sold. No one could therefore become the “master of the image of God.” Humans, as the image of God, were their own masters. Gregory’s words are the first principled articulation completely invalidating the institution of slavery.
Notice that when Gregory explains that all humans are judged equally by God, ascending after death to Heaven or descending to Hell, he draws on the same dualistic body-soul dichotomy we had seen above. Unlike the Stoics, however, for Christians the soul is also a locus of intersubjective relationships, as each and every soul subsists in a personal relationship with God. Thus it is not sufficient that one finds peace and freedom within while their body is enslaved. Human souls have supreme value in their own right, every soul is a unique subject, an autonomous and singular entity, by virtue of which it enjoys special worth, its status also compelling an appropriate standard of behavior from others toward it.
Gregory’s teachings demonstrate how profoundly conceptions of the individual changed with the rise of Christianity. The perception of the soul as the locus of redemption, under God’s gaze, which determined a person’s fate—in other words, the transformation of the soul into the focal point of religious life—made the individual the centerpiece of the religious drama. But this new focus on the soul, or on people’s inner lives in general, could not have instigated this revolution by itself. As we have seen, the Stoics solved the problem of slavery by focusing on the eternally-free soul. For them, the existence of the soul legitimized, rather than challenged, the prevailing state of affairs.
Unlike the Stoics, however, for Christian thinkers the soul is not a hidden refuge where one could find a modicum of freedom, but an extraordinary creation which stands in eternal relationship with the divine, it’s only true master, and to whom its whole existence must be dedicated. For them the person, in his or her distinct entirety, must be free, because the human person was the image of God, and thus a complete subject worthy of reverence.

According to Aristotle, the slave is “a living tool”, and according to Varro, a Roman educator from the first century BCE, slaves were “articulate instruments.” Jews and Christians could not have accepted such definitions, because these definitions deprived slaves of their humanity. They found it inconceivable that slaves be analogized to instruments, because to do so denied their existence as creations in God’s image.
Thus the ancient Hebrew laws mandating the treatment of the enslaved as human beings. Thus, when Christianity transforms the idea of freedom and privatizes it, the voices calling for complete rejection of slavery. Thus, issuing the universal Catechism of the Catholic Church, Pope John Paul II affirms that “Being in the image of God the human individual possesses the dignity of a person, who is not just something, but someone.” The individual was a subject and could not be turned into an object.
This guiding logic would accompany Western civilization all the way to the total abolition of slavery. In the late eighteenth century, the famous abolitionist William Wilberforce would still cry that all humans were created in God’s image and that slavery was therefore utterly illegitimate. The original French version of the popular Christmas carol O Holy Night, written in French by Placide Cappeau as Minuit, Crétiens in 1847, proclaims that Jesus “has broken all the shackles / The earth is free and heaven open / He sees a brother where there was once but a slave.”
Less than a decade later, writing in dissent of the majority verdict in the infamous case of Dred Scott v. Sanford (1856), Justice John McLean insisted in defiance of his colleagues on the United States Supreme Court that “A slave is not a mere chattel. He bears the impress of his Maker”.
The abolition of slavery is centered on the radical transformation in the understanding of the human person introduced by the idea that all people are created in the image of God. Over the centuries, this idea reshaped moral and legal frameworks, laying the groundwork for the eventual rejection of slavery as an institution, fueling abolitionist movements and embedding itself in the foundations of modern human rights discourse.
It is hard, indeed terrifying, to contemplate the possibility that lacking the idea of the creation in image of God the institution of slavery would have endured to this day. We must believe another moral or philosophical principle would have emerged to challenge it. Yet as much as we would like to think of our rights as self-evident and unalienable, a close examination of the history of the West reveals just how much we owe to that one clear and distinct idea, the idea that all human being were created in God’s image.
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