How does magnetism work at the molecular level?

This might give you pause: Simple bar magnets seem to be entirely able to pick up small metal objects, which certainly seems to require that they do work on those objects. As David J. Griffiths points out in his textbook Introduction to Electrodynamics, this law is absolute - the magnetic field doesn't do any work. However, quite like the normal force of an inclined plane, which also can't do work, the magnetic field can redirect the efforts of existing forces, and then those forces can indeed do work in the relevant direction.