In gauss law we say enclosed charge matters and integration E.da is field due to all charges but the ones out of the gaussian surface cancels out and hence we have q(enclosed) on the right hand side of the equation.Then what is the explanation for the Gauss law for gravitation?

Why at depth of a planet only the inner mass effectively pulls on an object
I know that considering the solid angle and distance the force equally cancels out for the outside points but still i am not sure how do in derive it
And also why does it not cancel out for the enclosed mass?