I am looking for a quote along the lines of "without the bad, we wouldn't recognize the good"?

That is just a rewording of the serpent's lie to Eve: "Ye shall be as gods, knowing good and evil." Can't you think of something a little more in touch with reality? I mean, good and evil are only opinions.

Without the dark we couldn't see the stars.

Or

Maybe you have to know darkness to appreciate the light.