Jesus expects and commands us to distinguish between wolves and sheep (Matt.7:15-16)
A wolf is known by his appetites. A wolf wants to use the sheep to fill his own lusts, and does not care about whether this hurts the sheep or not.
A man who rapes children is a wolf, not a misguided sheep.
A man who molests children is a wolf, not a misguided sheep.
A man who beats his wife, cheats on his wife, demands complete and absolute obedience from his wife, and believes that he is the voice of God in his home, is using his wife to fill his own lusts for self-importance, power, and self-worship to the hurt of his wife. He is a wolf, not a sheep.
A man who has his children in absolute terror, who holds or gives his favor to his family based upon his whims and his lusts for power and control is using his God-given authority to destroy and devour the sheep. He is a wolf, not a sheep.
And here is a biggie. Matthew 18:15-18 are the instructions of our Lord concerning brothers who have sinned against each other. They are not intended as instructions on how to deal with wolves. Wolves must be cast out and left in the hands of God. Wolves have no problem pretending to be sheep – even to the point of tears and all of the right words. But Jesus said that you will know them by the fruits, not by their tears and empty words.
Before you apply Matthew 18, you must ask yourself if you are dealing with a wolf or with a sheep. Jesus commanded us to tell the difference. You will know them by their fruits (see above).