This paper explores the role of the doctrine of emanation in the pantheism debate between Jacobi and Mendelssohn and its influence on later German Idealism. Their exchange raises two central questions: Is emanation an immanent process? And is it incompatible with creation from nothing? To clarify these issues, I will first outline the Neoplatonic background of emanation, which—contrary to some interpretations, including Kant's in The End of All Things—is not inherently pantheistic. I will then analyze how Spinoza, as described by Jacobi, fundamentally transforms the traditional doctrine of emanation into an immanent one. Finally, I will examine Mendelssohn's objection to Jacobi that emanation implies creation from nothing. Ultimately, German Idealism, under Spinoza's influence, became increasingly pantheistic and the doctrine of emanation itself became immanent and secularized.