I think that the prophecy describes what happens to Lucifer through out the the show. Rewatch season one, even on the early episodes of that season, they keep mention of Lucifer changing. Linda does said this line to Lucifer “That you are changing, but that you don’t know what’s causing the change. Or who” At the end of that same episode, Lucifer shows that he knows that Chloe is changing him. The next episode, he discovers that he likes seeking justice for the good people. And we do see that Lucifer becoming a better person as the show progresses. So evil being released could mean that the evil inside of will be gone.