What is the meaning of spiritual friendship?

Have faith in your spirit friends. 

They can do far more for you than you have the smallest idea of if you will only let them approach you as they wish. If when you are tried and tempted, you lift up your hearts to them (words are not necessary), they can help you to resist, and after you have obtained one or two victories over yourselves and your tempters, it will be easy and simple for you to do so again. Soon they will leave you. When they find they have no hold on you, they will relieve you of their presence and better and purer influences will take their place.

—T. P. in Spirit