Gauss' theorem, also known as the divergence theorem, relates volume integrals of the divergence of a vector field to surface integrals over the boundary of the volume. The transformation from the volume integral of the Laplace operator applied to a function J to the surface integral involves applying the divergence theorem. It is clarified that Gauss' Law cannot be used to prove this relationship, as the divergence theorem is a more general principle. The discussion confirms that understanding this process is essential for solving related problems. Overall, the divergence theorem is a fundamental tool in vector calculus for connecting volume and surface integrals.