I think that for a meme to be effective, it needs to be short, the fewer words the better, for easy memorization.
I like the idea of using the word "protect," rather than "defend." Defense is a reaction to a threat, whereas protection is more proactive. For example, I might build a sturdy house to protect my family from bad weather. Subtle distinction, but the connotations are different, "defense" specifically implies an attack, "protection" doesn't.
A take-off on the Scout motto: Be armed, Be prepared.
How about, "Criminals don't wait for you to prepare [load]."