Teach Freely

We Jews have a tradition that the Creator granted Moses his prophecy mainly for the sake of teaching the people. Like Moses, you never know for whose sake you were taught what you were taught. So it's wise to be generous with teaching others. 

For all you know, you might be just the agent designed to pass on a message to someone who can make better use of it than yourself. Still, don't feel dejected. Even if it seems like you were only intended as the straw for someone else's drink, with straws some drops always adhere to the walls. So, obviously some of the message was intended for you as well.