Angels are spirits with will and intelligence. The term “angel” comes from the Greek ἄγγελοσ (transliterated: ànghelos), equivalent of the Hebrew מַלְאַ֧ךְ (transliterated: malak), and means “messenger” (2 Samuel 11:18; Matthew 11:10). Therefore it indicates the function of these creatures which by nature are “spirit” (Hebrews 1:14). A name given to an angel indicates a particular assignment. For example, the angel who was sent by God and through whom old Tobi were healed of his blindness, and young Sarah from the devil who tormented her, is called “Raphael” for this particular task of his (Tobit 3:17), which means “God has healed”. In the canonical texts at our disposal, only three angels are mentioned by name: Michael, Gabriel and Raphael. Angels are not mentioned in the two creation accounts (Genesis 1-2), and therefore we cannot know exactly when they were created. From what we read in Job 38:4-7, it seems that angels were created before men. According to the thought of St. Augustine Ipponense, which we find in his writing “The City of God”, it is possible that the angels were created on the first day, in the same instant of light (Genesis 1:3-5). Since God made all things ordered, He also established the angelic orders: the lower ones subjected to the higher ones. There are therefore three angelic hierarchies, each made up of three orders: superior, intermediate and inferior. Starting from the hierarchy and order superior to all the others, according to the classification given by Dionysius (V-VI century), we have: seraphs, cherubs, thrones, dominations, virtues, powers, principalities, archangels, angels (The Celestial Hierarchy VI , II). The term angel is appropriate first of all to celestial spirits belonging to the lower order of the third hierarchy, but it can also be applied to celestial spirits of higher orders, since these can perform their functions (The Celestial Hierarchy V, I). Angels are not bodies nor are they naturally joined to bodies. Being spirits, angels are incorporeal and invisible. However, angels can form sensitive bodies that represent their spiritual properties. They don’t do it for themselves, but to communicate with men. According to St. Thomas Aquinas, angels form aerial bodies by condensing the air, what is necessary for the configuration of the body they want to assume (Sum Theological I, q 51, a 2, ad 3). He explains that, although air in its normal state of rarefaction can have neither shape nor color, however when it is condensed it can take shape and color, as the clouds demonstrate. In assumed bodies the angels can perform vital operations for what they have in common with the operations of inanimate things, such as movement or making a sound. On the other hand, they cannot carry out the vital operations proper to living beings, such as eating, or generating other living beings. Therefore, the conviction of those who see some sinful angels in those sons of God who took the daughters of men as wives and fathered children is erroneous (Genesis 6: 2-4). In fact, Christ teaches that angels do not take wives (Matthew 22:30). To communicate with men, angels do not speak through the body formed by them, but produce sounds in the air similar to those produced by the voice of men. Furthermore, the angels do not eat or drink, this being a vital operation proper to living beings. In the Bible we see some angels eating, but this is only appearance (Tobit 12:19). In body visions, angels are often described as beautiful young people with straw-white hair and white robes. The beautiful and luminous bodies, together with the white garments, externally show the sanctity and purity of these celestial spirits. Sometimes, especially in prophetic visions, angels are described with wings. Nothing is superfluous of the representation of the bodies formed by angels, since it designates their spiritual faculties, as Thomas Aquinas affirms. Therefore, as the eye indicates the cognitive virtue of angels, the wings instead indicate the agility in carrying out divine commands. They also indicate their heavenly residence. The local motion of the angels can be discontinuous and can also be continuous. In fact, angels can leave a place instantly, or they can progressively abandon it. Unlike men, angels do not need a certain amount of time to choose, to exhort and to consent. It is enough for an angel to express a wish with an intellectual phrase that, at the same instant, all the other angels can consent to it. Thus it was that Lucifer, having become Satan which means “Adversary”, expressed his desire and exhorted a third of the angels who at that same moment consented to it (Revelation 12:4).