If our persistent foe, who never ceases to persecute us, should assail us disguised as an angel of light, stand firm and steadfast even though cognizant of your own nothingness, and say to him boldly: "Return, miserable one into your realms of darkness; for I am unworthy of visions, nor do I need anything but the mercy of my Savior, and the prayers of Mary, Joseph and all the Saints."
And though these visions seem to bear many evidences of having been born in Heaven, still reject them as far as it is within your power to do so. And have no fear that this resistance, founded as it is on your own worthiness, will be displeasing to God. For if the vision be from Him, He has the power to make the same known to you, and you will suffer no detriment; for He Who gives grace to the humble does not withdraw it because of acts which spring from humility.
These, then, are the weapons which the enemy most commonly employs against us at the hour of our death. Each individual is tempted according to the particular inclination to which he is most subject. Therefore, before the zero hour of the great conflict, we should arm ourselves securely, and struggle manfully against our most violent passions, that the victory may be easier in that hour which leaves no future time for preparation or resistance.
- taken from The Spiritual Combat, by Father Lorenzo Scupoli