Addressed directly to "you," this short poem speaks to someone who is hiding from the world. The curtains are the obvious shield: a thin layer of fabric between a person and everyone outside. The speaker says plainly that they won't be enough to keep society away. Whatever is out there will still be out there, whether the windows are covered or not.
The last three lines turn the poem toward comfort, or at least toward a challenge. The only real protection is "you," meaning the person's own strength, confidence or sense of self. The speaker doesn't say how to find it, and that leaves the advice feeling both reassuring and a little demanding.
The tone is calm and steady, almost like a friend speaking quietly rather than lecturing. The short lines and the pauses between them make each phrase land slowly. The mood is serious but caring, with a sense that the speaker understands the urge to hide and still wants the reader to step out from behind the glass.