The first half of the 1990's saw an explosion of the number of books on angels. Many of these books contain touching accounts of the roles angels played in the salvation of people in their daily lives. Almost all these books advocate an openness to angels and a grateful acceptance of angels and their communications with mankind. Many of the authors encourage an angel-centered life and the hope for their regular influence and, at the same time, an awareness that angels sometimes appear in ways that are outwardly not very angelic.
Nearly all these books fail to consider that the devil and his legions of demons are fallen angels who can disguise themselves as angels of light to cause the destruction of our souls. From the letters of St. Paul (2 Cor. 11:14) to modern times, the writings of the Church describe how these fallen angels masquerade not only as angels of light but also as saints, the Virgin Mary, and Christ Himself.
For example, in his discussion of the importance of discrimination, St. John Cassian recounts how one monk caused his own death and how, in another instance, another monk was prepared to murder his own son. In both cases, demons disguised as angels were the cause (The Philokalia, vol. I). In a different time and place, the Kiev Caves Paterikon records that a young monk named Nikita did reverence to an angel of light who told him not to spend time in prayer, that the angel would do it for him because it was more important for Nikita to spend time reading. While the demon-as-angel prayed in his place, Nikita became clairvoyant. Soon he didn't even want to hear about the Gospels, preferring to become well versed in the Old Testament instead. His fellow monks, having finally perceived the demon, drove it away by prayer. Nikita repented and, through the grace of God, went on to become bishop of Novgorod, a shepherd to his flock, and a miracle-worker. We know him as St. Nikita the Recluse.
"Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravening wolves. Ye shall know them by their fruits. Do men gather grapes from thorns, or figs from thistles?" (Matt. 7:15-16). "But the fruits of the Spirit are love, joy, peace, long-suffering, gentleness, goodness, faith, meekness, temperance: against such there is no law. And those who are Christ's have crucified the flesh with its affections and lusts" (Gal. 5:22-24).
To put into practice these words of Christ and St. Paul in discriminating between real angels and demons masquerading as angels is difficult in the face of human frailty, our sinfulness, our self-willed delusion, and the thousands of years of experience of the enemy of man and God. Remember that the deluded monks described above had dedicated their very lives to Christ. The Holy Fathers of the Church, in their great love for us, tell us to pray, to seek humility, and to seek the guidance of a spiritual Father. They clearly tell us not to seek visions of angels and to be very questioning and skeptical when we do receive such visions. They tell us that if we have the slightest doubt about a vision, to say, in fact, "I do not know," and to put it aside or simply to reject it. They tell us that God will overcome our actions if God is the source and that the angels will rejoice at our humility and sobriety. (See the indices of The Philokalia, vols. I, III, and IV of the English edition, for some pertinent references.) What the Holy Fathers of the Church tell us is very different from what has been written by the authors of today's popular books.
The devil is a liar and a sower of confusion, and to accomplish his ends, he and his demons will lie to us not only by their words but also by masquerading as something they are not. Any other wordly phenomena that are sources of confusion and distraction (so-called alien abductions being a modern example) might be such a masquerade.