This equation says that the integral of the magnetic field B around the edge ⁠ ∂ ∂ S ⁠ of a surface S is equal to the integrated current J through any surface with the same edge, plus the displacement current term ⁠ ε ε 0 ∂ ∂ E / ∂ ∂ t ⁠ through whichever surface.