It is the teaching of the Church and theologians, and in accordance with what we read in the Old and New Testaments, that the angels, who are divine messengers, exercise a particular care and protection over individuals on earth, and help them in attaining salvation.

In Exodus (20:20), the Lord God told Moses, “I am sending an angel before you, to guard you on the way and bring you to the place I have prepared,” and after the angel had liberated St. Peter from prison, the latter remarked, “Now I know for certain that the Lord has sent his angel to rescue me from Herod’s clutches” (Acts 12:11). The common teaching of theologians is that every human being, not merely the baptized, has a special guardian angel from birth, and this they derive from Christ’s words: “Do not despise 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” (Matt. 18:10.)

Referring to the same text, St. Basil writes: “Every one of the faithful has an angel standing at his side as educator, and guide, directing his life” (Against Eunomius III, 1). Devotion to the angels began with St. Benedict and then steadily increased from the time of St. Gregory the Great to St. Bernard of Clairvaux, who was perhaps the most eloquent exponent of devotion to the Guardian Angels.

The final prayer in the Mass of the Holy Angels speaks of the angels keeping us free from danger in this life and bringing us to the joy of eternal life. A feast in honor of the Guardian Angels was celebrated in Valencia, Spain, as early as 1411; it then spread through Spain and into France. Pope Paul V introduced it into the Roman Calendar in 1608, and Pope Clement X later (1670) set its celebration for October 2.

~Joseph N. Tylenda, Saints and Feasts of the Liturgical Year (Washington, DC: Georgetown University Press, 2003), 210–211.