When do dark spirit-lives lose power to cross your path?

Away from the raging fiends, Spirit Franchezzo and his companion are borne away to a short distance.  

They look back, and see through the walls, which have become transparent to their eyes—

The whole mass of spirits—

Quarrelling and fighting with each other—

Like so many devils—

Each blaming the others that they had been allowed to escape.

Look now, says Faithful Friend, had you allowed yourself to join—

Even for a moment—

In any of their pursuits—

We would not have been able to help you, for you would have become clothed, for a time, with their material magnetism, and these walls would have held you—like them—prisoner, since you would have become too gross to pass through them. 

Those spirits are not done with you yet, and you must look to seeing them again, for even the brief time on the earth-plane, during which you yielded to their influence and thought of following their suggestions, has created a link between you and them, which it will be difficult to sever until you stand stand on a height of spiritual development, which will set a gulf between you. 

As yet, you have not fully overcome your own passions—

You have learned to subdue and control them, but all desire for revenge on those who wronged you in the past is not dead, and until that is so, you will not be able to shake yourself entirely free from these beings, especially while you are in their own particular sphere where they are strong. 

I have fought a battle not unlike that which you wage now and I know how hard it is to forgive where we have been deeply wronged. 

Yet I know also that you will do it thoroughly and freely some day and then will these dark spirits have lost power to cross your path.