Captive

In fact, wearing mutually opposing rings at the same time was an arduous task that severely tested one's will and perseverance. Will and fear were opposing emotions, their opposition on the Emotional Spectrum second only to that between the Black Lantern and White Lantern. Without a third ring to mediate them, directly wearing the Green and Yellow Rings and bringing them into contact would unleash power no different from Mars crashing into Earth. But the wearer first had to withstand that impact.