A lion hiding itself represents, we are told, the interior natural man. Evil tendencies lurk deep within the natural mind of man, and the hells flow into these evils, quietly encouraging the man to twist and pervert all that he learns from the Word. If the hells operated openly, they would pose far less of a threat, but by secretly encouraging us to explain away within ourselves the truth of the Lord's Word, they can bring about our downfall. Even though the Lord teaches us not to do something, we can so twist the truth in our minds that this truth is rendered powerless. And this happens slowly, quietly, in small steps.
Evil is something that sneaks up on a person, just like a lion.
We tell ourselves that it won't really matter if we do just one small thing that is wrong. But one small evil leads to another, quietly, without our hardly noticing it. And in this way the influence of the hells creeps up upon us, hiding behind our thoughts, hiding and preparing to pounce upon us and devour us. The thought of falling prey to the teeth of a lion is a horrifying thought. And yet hell also has its teeth, teeth which destroy not the body, but the soul.