There is no sadism, in the Krafft-Ebing sense of the term, in the opening pages of the Marquis de Sade’s novel Juliette. At the start of this thousand-page dream of crime, Sade rolls out a few orgies to highlight the beauty and intuitive depravity of his Juliette, and it is hardly surprising that he sets them in Pentemont Abbey – a Parisian convent. Juliette’s seducer is a fictional nun-libertine named Delbène, the abbess of Pentemont. So far, so Sadean.

It is notable, though, that Delbène and her clique only inflict pleasure on Juliette – never pain – in the novel’s opening scenes. It falls to Juliette to commit the novel’s first sadistic crime. And it is shortly before this horrific scene that Delbène says to her young protégé: ‘Refer yourself again and again to the great theses of Spinoza!’

This is eye-catching. The name of a monkish free-thinker, Benedict de Spinoza, is placed at the head of Sade’s sick novel. What is more, Juliette ends with its murderous and incestuous (and worse) anti-heroine saying to her partners in crime: ‘Truth itself, and truth alone, lays bare the secrets of Nature, however much mankind may tremble before those revelations. Philosophy must never shrink from speaking out!’

Clearly, in Sade’s mind, Juliette is a philosophical novel. And Delbène’s invocation of Spinoza seems to place it in a genre that Jonathan Israel calls the Spinozistic novel, meaning a work that is consciously inspired by Spinoza’s tradition-threatening system. Which could lead us to ask: Is Sade’s Juliette – this grim summa of atheistic criminality – really Spinozistic?

It is not, but the reason we can say that ‘BdS’ – as many libertines called him – is not the one who inspired Sade, is far from obvious. For Spinoza is a mechanistic and deterministic philosopher, which is why Sade invokes him. He is cited as an atheist – or, as some styled him, the ‘prince of atheists’ (atheorum princeps). And yet, Spinoza’s theory of human liberation – which he also calls salvation – is totally opposed to Sade’s. This is, in part, because Spinoza thinks highly of Jesus and his ethic of love – where Sade detests both.

The intrusion of Jesus’ name here is less odd than it might strike us. As we will see, Jesus was a decisive influence on Spinoza’s thought. It is intriguing, too, that Sade turns his attention to Jesus, soon after Delbène instructs young Juliette to drill herself in the ‘theses of Spinoza’.

Who is Sade’s Jesus? He is a ‘sinister little cheat’ and a ‘stammering little bore’. His habit of dining with morally compromised characters, in the Gospels, is held against him in Juliette. Delbène looks down on his ‘suppers with sluts’ (to call Sade hypocritical, here, doesn’t cut it). ‘How does Jesus gain my belief in him?’, Sade’s abbess-infidel asks. ‘By abjectness, poverty, imposture.’ And how does he perish? ‘Hanged up there on a cross.’ In short, says Delbène: ‘I’ve omitted nothing from the portrait, and in it there’s not one feature that stirs the soul or appeals to the heart.’

Sade’s Jesus is an impostor. Note the word. For this is how Jesus is portrayed, alongside Moses and Muhammad, in one of the hardest-edged clandestine texts of Europe’s long 18th century, The Treatise of the Three Impostors. Further, in a curious twist of literary history, this anti-Christian (and anti-Judaic and anti-Islamic) samizdat often circulated under the heading, The Spirit of Spinoza. One consequence of this chic misbranding is that Sade might have thought his impostor-Jesus was inspired by Spinoza. If he did, then in this – as in so much else – Sade was wrong.

Étienne Balibar, a contemporary French philosopher, claims that Spinoza’s ‘true problem’ in his scandalous Theological-Political Treatise is ‘that of the meaning of Christianity’. Though Balibar does not elaborate, this claim becomes less disorienting once we recall Spinoza’s well-documented ties to dissident Christians in the Netherlands. We must give due weight, too, to the fact that Spinoza, as Jacob Taubes notes, ‘speaks about the Apostle Paul in the highest, most reverential terms’. Taubes is not in error, here – but he is inexact. For Spinoza does not speak of Paul of Tarsus in the highest terms. Rather, the Portuguese-Dutch free-thinker consistently speaks most reverentially about the one he calls Christ.

Spinoza’s Christ is the figure – and the only figure – whom he describes as ‘the mouth-piece of God’. And what could that mean for an unflinchingly naturalistic philosopher like the author of the Theological-Political Treatise and Ethics?

It is worth noting, first, that Spinoza subtly contrasts the figures of Moses and Christ. ‘The supreme prophet’ is Moses, and Spinoza seems to have called Jesus, in conversation, ‘the supreme philosopher’. In what do they differ? And why is Spinoza’s Jesus singular? This is something he underscores in the first chapter of his Theological-Political Treatise, where he writes:

We assert therefore that, apart from Christ, no one has received revelations from God except by means of the imagination, namely by means of words and visions, and therefore prophecy does not require a more perfect mind but a more vivid imagination.

In Moses, and in all the prophets of what Spinoza calls the Old Testament, the impulse to prophesy comes from the power of human imagination. Every prophet ‘undoubtedly saw God’, he argues, ‘as he was accustomed to imagine him’.

Yet Spinoza seems to believe that Christ’s inspiration has a different source. This is why he is ‘not so much a prophet’ in the Treatise, ‘as the mouth-piece of God’. And if Spinoza’s Jesus is ‘the mouth-piece of God’ and ‘the supreme philosopher’, it must be the case that his sayings were inspired by a unique apprehension of God-or-Nature, and thus, by reason (rather than imagination).

It is this distinction between reason and imagination that brings us to one of the most enigmatic passages in Spinoza’s Treatise, where we read this:

I do not believe that anyone has reached such a degree of perfection above others except Christ, to whom the decrees of God which guide men to salvation were revealed not by words or visions but directly… Therefore the voice of Christ may be called the voice of God, like the voice which Moses heard… If Moses spoke with God face to face as a man with his friend… Christ communicated with God from mind to mind.

There seems to be an uncanny sense, here, in which the figure (or non-figure) in scripture that Jesus is most like – per Spinoza – is God.

Note well: Spinoza believes in nothing more than the prodigious humanity of Jesus. He is patently unconvinced by Christian doctrines of ‘incarnation’ (although all he hazards in the Treatise is: ‘I do not understand them’). What is more, his only conception of God is that of a perfect and infinite, all-generating Nature. If ‘the voice of Christ may be called the voice of God, like the voice which Moses heard’ – and if Spinoza means this (and I think he does) – then this must be convertible into a seemingly less mystical line: ‘The voice of Christ may be called the voice of Nature, like the voice which Moses heard.’

And what could that mean? How could Jesus have spoken with a voice that Spinoza regarded – whether we agree with him or not – as the voice of Nature? And how could Moses, too, have once heard that voice of Nature? Could that be a serious thought, however obscure, at the heart of one of modern Europe’s most unnerving texts?

Spinoza’s celebrated doctrine, in the first pages of his posthumous Ethics, is: ‘All things that are, are in God and must be conceived through God.’ He takes this to mean nothing other than: ‘All things that are, are in Nature and must be conceived through Nature.’ And he takes that to be something that the Apostle Paul believed, too. As Spinoza writes in a letter: ‘That all is in God and moves in God, is something I affirm’ – he then adds – ‘together with Paul.’

Spinoza is thinking, here, of a line in Paul’s Athenian discourse in the New Testament, where he draws on ‘pagan’ poets to make his then-novel Christian case. ‘”In him we live and move and have our being”’, says Paul, ‘as even some of your own poets have said, “For we too are God’s offspring”’ (Acts of the Apostles 17:28). In Spinoza’s mind, both Paul and his ‘pagan’ sources are talking about God-or-Nature, whose offspring we are.

But if all things belong to God-or-Nature, so too does ‘human powerlessness in governing and restraining the emotions’, a state of life or being that Spinoza calls ‘servitude’. The same thought is expressed in his Treatise, where we read: ‘Those who live under the sway of pleasures are lost.’ Why lost? Because in servitude.

The question, here, is not whether this sequence of thoughts is convincing – only whether it can help us to glimpse a serious thought in Spinoza’s strange text on Moses, Christ, and the voice of God-or-Nature. And it can.

Spinoza holds that ‘desire is the very essence of a human being’. It is because of this – our desirous essence – that humans come to ‘live under the sway of pleasures’ and, thus, to be ‘lost’. It is because of this, too, that humans can desire to be ‘saved’. And what can save us, Spinoza asks, from the controlling influence of pleasure? And what, in that way, can reconcile us to God-or-Nature – that is, to the totality of Being?

Spinoza’s answer to this question is – strangely – love. He writes that ‘love of one’s neighbour’ is the only ‘rationale of living’ by means of which we can be, as he puts it, saved. At first glance, this seems to be hardly convincing. Yet it is in line with what Spinoza calls ‘the dictates of reason’. We read this, for instance, in his Ethics:

Human beings, I say, can wish for nothing better for preserving their own being than that all should agree in all things, so that… all of them simultaneously… pursue what is useful for all in common.

What prevents this state in which ‘all agree in all things’? Hatred. And if hatred is both corrosive and enslaving, then what is liberating? This is Spinoza, again, in Ethics:

A person who lives by the command of reason endeavours as far as he can to repay the hatred, anger, disdain, etc. of another person towards himself with love.

This vision of a reason-liberated person appears in the work’s concluding pages, where love is a theme. He writes even later in his opus magnum that striving to love others is ‘the endeavour of the better part of ourselves’ to exist in harmony with ‘the order of the whole of nature’. In other words, human love is a rational imitation of the totality of God-or-Nature. And that is what Spinoza calls ‘the path that leads to freedom’.

It is reasonable to ask: have we heard before of ‘a command to repay with love the hatred, anger, or disdain others’? And if so, where might we have heard this ‘dictate’, which Spinoza ascribes to reason (and not to prophetic imagination)?

Is there not a similar command in Jesus’ Sermon on the Mount, which Spinoza cites in the Treatise – and which Jacques Derrida once called, with acute sensitivity, a ‘sermon on the heart’? We read this in the Gospel According to Matthew:

I say to you, Love your enemies and pray for those who persecute you, so that you may be children of your Father in heaven; for he makes his sun rise on the evil and on the good, and sends rain on the righteous and on the unrighteous… Be perfect, therefore, as your heavenly Father is perfect. (Matthew 5:43–48)

Again, our question is not whether this sequence of thoughts is convincing – only whether it helps us to glimpse something serious in Spinoza’s mystifying lines on Christ, and Moses, and the voice of God-or-Nature. Again, it does.

For whatever we make of it, we note that the ‘perfection’ Jesus urges is not only an imitation of God, but of Nature. The skies, in their non-judgement of ‘the evil and the good’, might be taken to be something like God-or-Nature avant la lettre. And who is instructing us, here, to imitate God-or-Nature? ‘I say to you’, says Jesus. Is he not, here, very much like the voice of Spinoza’s God-or-Nature?

This, I think, is the strangeness of Jesus in Spinoza’s corpus. For Jesus is both a ‘rabbi’ and a ‘prophet’ in the Gospels (see ‘prophet’ in Mark 6:15, ‘rabbi’ in John 1:38, and many other places). And yet, unlike the prophets and rabbis of antiquity – unlike the apostles, too – Jesus often speaks with a sublime and uncanny ‘I’ that we could take (or mistake) for the indestructible substance that Spinoza calls God-or-Nature.

As already mentioned, this has nothing to do with the Christian doctrine of incarnation. It has only to do with what Spinoza sees as the Gospels’ delineation of a ‘universal religion’, by which he means, a religion that is ‘supremely natural’. This so-called natural religion – a concept with innumerable 18th- and 19th-century echoes – must not be confused with historical Christianity, or historical Judaism. Yet it has deep roots in both.

Spinoza is struck by a passage in the New Testament which ‘explains God’ – in his words – ‘by love alone’, and ‘concludes that he who has love, truly has God’. Spinoza has in mind, here, a couple of verses in a letter attributed to one of Jesus’ original disciples, John, where we read this: ‘Beloved, let us love one another, because love is from God. Everyone who loves… knows God … for God is love’ (I John 4:7–8).

What is the free-thinker’s gloss on this verse? ‘Jeremiah, Moses and John’, he writes, ‘summarise’ this knowledge of God – namely, the knowledge of love. Spinoza then cites a text from the prophet Jeremiah, where we read in the voice of God (or Nature): ‘Let those who boast, boast in this, that they… know me, that I am the LORD; I act with steadfast love’ (Jeremiah 9:23–24). As this shows, Spinoza draws his ethical imperative to love (which is not a political imperative) from books which are attributed – by tradition, if not always by him – to prophets and apostles. This imperative is decisive in both his Treatise and Ethics.

Some of the very last thoughts in Spinoza’s Ethics are basically a paraphrase of the verses we have just read in the New Testament. The philosopher writes, much like John: ‘Insofar as God loves himself, he loves human beings.’ And again: ‘We clearly understand from all this what our salvation… consists in, namely… the love of God for human beings.’ It is God-or-Nature’s love, and a consequent rule that we humans should love others, that Spinoza finds in certain prophetic texts by Moses, Jeremiah, and John – but that he hears most rationally articulated in the sayings of Jesus.

More could be said about ‘the love of God for human beings’ in Spinoza’s radical oeuvre, but his many statements on love all seem to confirm that there is a naturalistic sense in which the one he calls Christ is singular. Jesus really does seem to be Spinoza’s ‘supreme philosopher’.

This is why he can write that ‘the decrees of God which guide men to salvation’ were brought by the Gospels’ divisive protagonist. These decrees of God are what Spinoza also calls dictates of reason. And although his Jesus is only human, he seems to have taught – like Moses, the prophets and apostles, but with an eery singularity – that love is the supreme decree of God-or-Nature. And thus, that we cannot hope for true liberation unless we ‘endeavour to repay the hatred, anger, and disdain of others with love’.

Spinoza’s philosophy is intensely hostile to the spirit of Sade, in part because of Spinoza’s heterodox, yet reverent idea of Jesus. For this iconic Jewish freethinker, ‘Christ’s deeds and passion’ are not a history of delusion. They are a real human memory of the lightning-like moment in which ancient religious imagination was illuminated by Jesus’ reason, and ‘the way of salvation’ became a universal question of love.