Who shall roll, &c. ? That was their only difficulty; therefore they could not have heard about the sealing and the watch. This is a Divine supplement, peculiar to Mark.
shall = will.
roll us away. The ground being on an incline (sideways), therefore the door was more easily closed than opened.
from = cut of (Gk. ek.App-104.): out of the bottom of the incline. Not the same word as in Mar_16:8. L and TR read apo (App-104.), away from, as in Mar_16:8.