Jesus gives us fairly straightforward criteria for discerning good and evil. Many times, when what is evil takes the form of dogs or pigs we can recognize it a mile away. Capital sins are supposed to be of that sort: murder, fornication, deception, etc. Sometimes evil takes the appearance of sheep though. They are wolves hiding in sheep’s clothing when what they say delights or entices but leads to sin. This is the most pernicious attack of the enemy, because we are in some ways fooled and consent to evil while we were unable to grasp the necessary relationship between what seems to be good and its evil consequences. We see this in gossip: sometimes what starts as simply giving people updates turns into complaining about others, or spreading rumors about what others have said or done. We see it in murder: sometimes what starts as taking a stand against apparent injustice ends in the death of another. We see it in fornication: what starts as pleasant affection ends in the act reserved for marriage. We see it in greed: what starts as working to have enough turns into getting as much as possible by any means necessary. The key to identifying the wolf is trying to see where what seems to be good actually leads.