And his hands would plait the priest’s entrails,
For want of a rope, to strangle kings.

[Et ses mains ourdiraient les entrailles du prêtre,
Au défaut d’un cordon pour étrangler les rois.]

Denis Diderot (1713-1784) French editor, philosopher
Poem (1772), “Les Éleuthéromanes”
    (Source)

The work is also sometimes referred to as "Dithrambe sur fête de rois."

(Source (French)). Other translations:

And his hands would plait a priest's entrails;
In lieu of a rope for strangling kings.
[Source]

His hands would plait the priest’s guts,
if he had no rope, to strangle kings.
[E.g.]

Jean-François de La Harpe, Lycée, ou Cours de Littérature Ancienne et Moderne (1822), attributes this variant to Diderot as the "crowning touch" of his philosophy:

With the guts of the last priest,
Let us strangle the last king
 
[Et des boyaux du dernier prêtre
Serrons le cou du dernier roi.]

Alternately:

And [with] the guts of the last priest
Let's shake the neck of the last king.
[E.g.]

This phrasing of Diderot's is most likely derived from a passage by Jean Meslier (c. 1664–1733), a French priest. In his Testament [Common Sense], Vol. 1, ch. 2 [ed. Charles (1864)], he told (and approved) of an "ignorant, uneducated man" who said (English, French):

He said he wished [...] that all the great men in the world and all the nobility could be hanged, and strangled with the guts of priests.
 
[Il souhaitoit [...] que tous les grands de la terre et que tous les nobles fussent pendus et étranglés avec les boïaux des prêtres.]

Other translations of Meslier:

His wish was that all the rulers of the earth and all the nobles be hanged and strangled with the guts of priests.
[tr. Shreve (2009)]

Bill Brown, the 2007 translator of Veneigem's The Resistance to Christianity (1993), noted that Voltaire, who edited an early edition of Meslier's Testament, rewrote the passage to provide another French variant (with Brown's English translation):

I would like, and this would be the last and most ardent of my wishes, I would like it that the last king was strangled with the guts of the last priest.
 
[Je voudrais, et ce sera le dernier et le plus ardent de mes souhaits, je voudrais que le dernier des rois fût etranglé avec les boyaux du dernier prêtre.]

Other variants, in general:
  • "Men will never be free until the last king is strangled with the entrails of the last priest."
  • "Humanity will only be happy when the last priest has been hung with the guts of the last prince."