That every individual soul has a guardian angel has never been defined by the Church, and is, consequently, not an article of faith; but it is the "mind of the Church", as St. Jerome expressed it: "how great the dignity of the soul, since each one has from his birth an angel commissioned to guard it." (Comm. in Matt., xviii, lib. II).
This belief in guardian angels can be traced throughout all antiquity; pagans, like Menander and Plutarch (cf. Eusebius, "Praep. Evang.", xii), and Neo-Platonists, like Plotinus, held it. It was also the belief of the Babylonians and Assyrians, as their monuments testify, for a figure of a guardian angel now in the British Museum once decorated an Assyrian palace, and might well serve for a modern representation; while Nabopolassar, father of Nebuchadnezzar the Great, says: "He (Marduk) sent a tutelary deity (cherub) of grace to go at my side; in everything that I did, he made my work to succeed."
In the Bible this doctrine is clearly discernible and its development is well marked. In Genesis 28-29, angels not only act as the executors of God's wrath against the cities of the plain, but they deliver Lot from danger; in Exodus 12-13, an angel is the appointed leader of the host of Israel, and in 32:34, God says to Moses: "my angel shall go before thee." At a much later period we have the story of Tobias, which might serve for a commentary on the words of Psalm 90:11: "For he hath given his angels charge over thee; to keep thee in all thy ways." (Cf. Psalm 33:8 and 34:5) Lastly, in Daniel 10 angels are entrusted with the care of particular districts; one is called "prince of the kingdom of the Persians", and Michael is termed "one of the chief princes"; cf. Deuteronomy 32:8 (Septuagint); and Ecclesiasticus 17:17 (Septuagint).
This sums up the Old Testament doctrine on the point; it is clear that the Old Testament conceived of God's angels as His ministers who carried out his behests, and who were at times given special commissions, regarding men and mundane affairs. There is no special teaching; the doctrine is rather taken for granted than expressly laid down; cf. 2 Maccabees 3:25; 10:29; 11:6; 15:23.
But in the New Testament the doctrine is stated with greater precision. Angels are everywhere the intermediaries between God and man; and Christ set a seal upon the Old Testament teaching: "See that you despise not one of these little ones: for I say to you, that their angels in heaven always see the face of my Father who is in heaven." (Matthew 18:10). A twofold aspect of the doctrine is here put before us: even little children have guardian angels, and these same angels lose not the vision of God by the fact that they have a mission to fulfill on earth.
Without dwelling on the various passages in the New Testament where the doctrine of guardian angels is suggested, it may suffice to mention the angel who succored Christ in the garden, and the angel who delivered St. Peter from prison. Hebrews 1:14 puts the doctrine in its clearest light: "Are they not all ministering spirits, sent to minister for them, who shall receive the inheritance of salvation?" This is the function of the guardian angels; they are to lead us, if we wish it, to the Kingdom of Heaven.
St. Thomas teaches us (Summa Theologica I:113:4) that only the lowest orders of angels are sent to men, and consequently that they alone are our guardians, though Scotus and Durandus would rather say that any of the members of the angelic host may be sent to execute the Divine commands. Not only the baptized, but every soul that cometh into the world receives a guardian spirit; St. Basil, however (Homily on Psalm 43), and possibly St. Chrysostom (Homily 3 on Colossians) would hold that only Christians were so privileged. Our guardian angels can act upon our senses (I:111:4) and upon our imaginations (I:111:3) — not, however, upon our wills, except "per modum suadentis", viz. by working on our intellect, and thus upon our will, through the senses and the imagination. (I:106:2; and I:111:2). Finally, they are not separated from us after death, but remain with us in heaven, not, however, to help us attain salvation, but "ad aliquam illustrationem" (I:108:7, ad 3am).
Feast of Guardian Angels
This feast, like many others, was local before it was placed in the Roman calendar. It was not one of the feasts retained in the Pian breviary, published in 1568; but among the earliest petitions from particular churches to be allowed, as a supplement to this breviary, the canonical celebration of local feasts, was a request from Cordova in 1579 for permission to have a feast in honor of the guardian angels. (Bäumer, "Histoire du Breviaire", II, 233.) Bäumer, who makes this statement on the authority of original documents published by Dr. Schmid (in the "Tübinger Quartalschrift", 1884), adds on the same authority that "Toledo sent to Rome a rich proprium and received the desired authorization for all the Offices contained in it, Valencia also obtained the approbation in February, 1582, for special Offices of the Blood of Christ and the Guardian Angels."
So far the feast of Guardian Angels remained local. Paul V placed it (27 September, 1608) among the feasts of the general calendar as a double "ad libitum" (Bäumer, op. cit., II, 277). Nilles gives us more details about this step. "Paul V", he writes, "gave an impetus to the veneration of Guardian Angels (long known in the East and West) by the authorization of a feast and proper office in their honor. At the request of Ferdinand of Austria, afterwards emperor, he made them obligatory in all regions subject to the Imperial power; to all other places he conceded them ad libitum, to be celebrated on the first available day after the Feast of the Dedication of St. Michael the Archangel. It is believed that the new feast was intended to be a kind of supplement to the Feast of St. Michael, since the Church honored on that day (29 September) the memory of all the angels as well as the memory of St. Michael (Nilles, "Kalendarium", II, 502). Among the numerous changes made in the calendar by Clement X was the elevation of the Feast of Guardian Angels to the rank of an obligatory double for the whole Church to be kept on 2 October, this being the first unoccupied day after the feast of St. Michael (Nilles, op. cit., II, 503). Finally Leo XIII (5 April, 1883) favored this feast to the extent of raising it to the rank of a double major.
Such in brief is the history of a feast which, though of comparatively recent introduction, gives the sanction of the Church's authority to an ancient and cherished belief. The multiplicity of feasts is in fact quite a modern development, and that the guardian angels were not honored with a special feast in the early Church is no evidence that they were not prayed to and reverenced. There is positive testimony to the contrary (see Bareille in Dict. de Theol. Cath., s.v. Ange, col. 1220). It is to be noted that the Feast of the Dedication of St. Michael is amongst the oldest feasts in the Calendar. There are five proper collects and prefaces assigned to this feast in the Leonine Sacramentary (seventh century) under the title "Natalis Basilicae Angeli in Salaria" and a glance at them will show that this feast included a commemoration of the angels in general, and also recognition of their protective office and intercessory power. In one collect God is asked to sustain those who are laboring in this world by the protecting power of his heavenly ministers (supernorum . . . . praesidiis . . . . ministrorum). In one of the prefaces, God is praised and thanked for the favor of angelic patronage (patrociniis . . . . angelorum). In the collect of the third Mass the intercessory power of saints and angels is alike appealed to (quae [oblatio] angelis tuis sanctisque precantibus et indulgentiam nobis referat et remedia procuret aeterna" (Sacramentarium Leonianum, ed. Feltoe, 107-8). These extracts make it plain that the substantial idea which underlies the modern feast of Guardian Angels was officially expressed in the early liturgies. In the "Horologium magnum" of the Greeks there is a proper Office of Guardian Angels (Roman edition, 329-334) entitled "A supplicatory canon to man's Guardian Angel composed by John the Monk" (Nilles, II, 503), which contains a clear expression of belief in the doctrine that a guardian angel is assigned to each individual. This angel is thus addressed "Since thou the power (ischyn) receives my soul to guard, cease never to cover it with thy wings" (Nilles, II, 506).
For 2 October there is a proper Office in the Roman Breviary and a proper Mass in the Roman Missal, which contains all the choice extracts from Sacred Scripture bearing on the three-fold office of the angels, to praise God, to act as His messengers, and to watch over mortal men. "Let us praise the Lord whom the Angels praise, whom the Cherubim and Seraphim proclaim Holy, Holy, Holy" (second antiphon of Lauds). "Behold I will send my angel, who shall go before thee, and keep thee in thy journey, and bring thee into the place that I have prepared. Take notice of him, and hear his voice" (Exodus 23; capitulum ad Laudes). The Gospel of the Mass includes that pointed text from St. Matthew 18:10: "See that you despise not one of these little ones: for I say to you that their angels in heaven always see the face of my Father who is in heaven." Although 2 October has been fixed for this feast in the Roman calendar, it is kept, by papal privilege, in Germany and many other places on the first Sunday (computed ecclesiastically) of September, and is celebrated with special solemnity and generally with an octave (Nilles, II, 503).