In his Doctrine of Right, Immanuel Kant calls Moses Mendelssohn, the towering figure of the German and the Jewish Enlightenment, a ‘Rechtsforscher’ – a legal scholar. Yet not only Kant, but numerous scholars of natural law in the eighteenth and nineteenth centuries, refer to and reflect on the juridical aspects of Mendelssohn’s work, in particular his thoughts on the law of contract. In this paper, I hope to shed some light on this hitherto rather unexplored facet of Mendelssohn’s oeuvre. Mendelssohn develops his theory of contract from the starting point of the officium amoris: the unenforceable ‘duty of love’ to exercise beneficence. Mendelssohn’s theory knows nothing yet of the modern contrast between altruism, distributive justice, and ‘freedom of contract'. By exploring Mendelssohn’s theory, we will, thus, be able to catch a glimpse of the birth pangs of the modern Western discourse on the ‘freedom of contract', which formed the backdrop, as well as the jumping-off point, of the development of a ‘liberal’ will theory of contract. Since this ‘liberal’ model is still the paradigm of how contract is mostly perceived today, Mendelssohn’s theory also exemplifies the possibility of an alternative to our own conceptualizations of contract that inescapably shape the way we think.