“A Warrior knows that an angel and a devil are both competing for his sword hand.
The devil says: “You will weaken. You will not know exactly when. You are afraid.” The angel says: “You will weaken. You will not know exactly when. You are afraid.”
The Warrior is surprised. Both the angel and the devil have said the same thing.
The devil continues: “Let me help you.” And the angel says: “I will help you.”
At that moment the Warrior understands the difference. The words may be the same but these two allies are completely different.
And he chooses the angel’s hand.”
― Paulo Coelho, Warrior of the Light
This quote excerpted from Coelho’s manual says that, in my own interpretation, the good and the evil both knows exactly someone’s weaknesses, but they differ in purpose: the devil will help you once you allow him to enter your life given certain conditions while the angel will help you, no matter what and without prior conditions at all.