“Many luminous spirits that have already left the earth are also eager to help human beings, but they cannot do so because there is no place fit for them to come to. Nothing has been got ready for them, so they have no right to come. You will certainly be astonished by this and say, ‘But I thought they had the power to do anything!’ Yes, they have every power, but they respect the law, and the law says that they have no right to enter somewhere by force.. Well, surprising or not, that is how it is. The entities of the invisible world cannot do whatever they want, and if they go somewhere without permission they will be punished for it.
The great mages, who know these laws, guard the places they particularly want to keep safe by means of magic formulas or symbols, which prevent malicious spirits from breaking in. This is necessary, because if no obstacle is put in the way of the inferior spirits they break in and wander about and do all kinds of damage.
Unlike the spirits of light, the malicious spirits don’t wait for a specific invitation before entering; they have no great respect for these laws. They will refrain from entering a place only if they are expressly forbidden to do so by divine powers, because they know that if they disobeyed they would be pulverized.
But, if you don’t actually forbid them to come in, they will not hesitate to do so. And, after all, you cannot really blame them: if you let them do what they want, why should the lord punish them? Humans have all the powers they need to oppose the spirits of darkness and say no to them. So it is entirely up to you to keep them out and to invite luminous spirits to come in, instead, and help you build a strong and beautiful inner sanctuary.”