Sometimes, a very lofty, very spiritual desire can trigger an immediate reaction of opposition from your lower nature. The higher and lower worlds are closely linked, and a magnificent aspiration on high can awaken opposing forces and desires in the roots of your being.
Of course, if disciples are knowledgeable and enlightened, these schemes of their lower nature have less chance of being successful, for they know that while they are working, meditating and building, they must surround themselves with beings who keep watch over them and protect them.
A highly evolved disciple takes the necessary precautions.
Moreover, in the early forms of Freemasonry, which were based on true science, the mason at work was portrayed with a trowel in one hand, and a sword with which to defend himself in the other.
So, while the mason worked, he kept watch to ensure that no enemy slipped in and captured the fortress under the cover of darkness.