(1) Is God willing to prevent evil, but not able? Then he is not omnipotent.
(2) Is he able, but not willing? Then he is malevolent.
(3) Is he both able and willing? Then whence cometh evil?
(4) Is he neither able nor willing? Then why call him God?The original quote is attributed to Epicurus.
So essentially the quote breaks down two binomial statements "Is God able to prevent evil?" and "Is God willing to prevent evil?". I think both statements are interesting but irrelevant.
Personally I wouldn't make assertions about the first statement (can God prevent evil). I don't find myself compelled to believe that he can or not. The fact that God created the Devil and thus Hell by opposing Gabriel has been rehashed by many people. It's the contradiction that by shining light one creates shadows. In the mathematical sense it's the assertion that the positive integers automatically create the negative ones (i.e. solve x + 1 = 0). Whether he has the mythical force or not is somewhat irrelevant to me.
The interesting bit is the second statement (is God willing to prevent evil). Personally, I don't think he'd be much of a God if he did prevent evil. It's almost the same assertion as "should a parent prevent any harm to their child, even if it means inhibiting their freedoms" or then looking at the subsequent statement "at which point does a parent do more harm by inhibiting freedoms". To look at it an alternate way, I once read a fascinating book that asserted that the faith was basically isomorphic to thermodynamics. To paraphrase that somewhat, as time proceeds linearly the world proceeds into disorder and no assertion within the system can improve this. The universe is a massive sorting machine of souls into good and evil, and the gears of that machine are existence on the earthly plane. You cannot have saints like Mother Theresa without sinners like Hitler.
Looking at it alternately (i.e. in the Newtonian force sense), the force caused by good or evil is always influenced by a natural acceleration towards disorder. That is, the same act of good has less net force as the universe tends to a disordered state. That means as an individual who wishes to influence the world positively, you need to amplify your "mass" as you will never have the "acceleration" that evil does. It is always easier to hate, to distrust, to envy... If it wasn't easier to do evil then doing good wouldn't be so meaningful. If the world that we lived in was Heaven then there would be no conflict, no development, no "sorting".
I sincerely do not understand how a God who interfered and artificially made the world a positive place would be a good thing. We need pain and suffering to make our lives meaningful, however that comes about. That doesn't mean we have to like it, but I don't find quotes like Epicurus made in any way meaningful, personally.