“It was just at this moment that Bilbo suddenly discovered the weak point in his plan. Most likely you saw it some time ago and have been laughing at him; but I don’t suppose you would have done half as well yourselves in his place. Of course he was not in a barrel himself, nor was there anyone to pack him in, even if there had been a chance! It looked as if he would certainly lose his friends this time (nearly all of them had already disappeared through the dark trap-door), and get utterly left behind and have to stay lurking as a permanent burglar in the elf-caves for ever.”
Such is the nature of evil. Out there in the vast ignorance of the world it festers and spreads. A shadow that grows in the dark. A sleepless malice as black as the oncoming wall of night. So it ever was. So will it always be. In time all foul things come forth.