As soon as we become aware of a thought that has an evil look about it, we must dismiss it immediately. We must, as it were, slam the door in its face, denying it admittance into the mind, without stopping to decipher its meaning or intention. We must shake off such wicked suggestions as quickly as we would shake off fiery sparks that landed on our clothes.
–Saint Alphonsus Liguori (1696-1787)