The question is as follows:
Let $L$ be a language (not necessarily regular) over an alphabet. Show that if the equivalence class containing the empty string $[ \epsilon ]$ is not $\{ \epsilon \}$, then it is infinite.
How do I go about answering this? Would I need to use Myhill-Nerode theorem? From what I've read there's a corollary from the theorem that if a language defines an infinite set of equivalence classes, it is not regular. I'm not sure if that helps answer my question though.