When a person discusses devotion with a friend, it creates "direct light" and "returning light." Sometimes the "returning light" comes before the "direct light" as when the recipient has certain mental limits that prevent him from accepting his friend's words. Even before the recipient receives the "direct light" from his friend, the friend already receives "returning light".
Even if the intended recipient cannot accept his friend's words, the friend can be inspired by what he himself is saying. When his words come forth from his mouth and strike the other, the light is reflected back to the speaker just as when something thrown against a wall bounces back to the thrower. In the same way, when you speak to a friend, you can be inspired by the words that bounce off him even though he himself is unable to accept them.
Had you told yourself exactly the same thing, it may be that you would not have been aroused in the least. But by addressing them to your friend, you yourself are inspired even if he is not, because your words are reflected back to you from your friend. - Likutey Moharan I, 184