A guardian angel is a spirit who is believed to protect and to guide a particular person. The concept of tutelary angels and their hierarchy was extensively developed by Pseudo-Dionysius the Areopagite, in the 5th century.

The belief that God sends a spirit to watch every individual was common in Ancient Greek philosophy, and Plato mentions the belief in Phaedo, 108. Similarly, the belief appears in the Old Testament, although it is not specifically articulated or delineated. Enoch 100:5 says that the just have protecting angels. In Acts 12:15 there is another allusion to the belief. In the Gospel of Matthew 18:10, Jesus says that children are protected by guardian spirits:

"Never despise one of these little ones; I tell you, they have their guardian angels in heaven, who look continually on the face of my heavenly Father." (New English Bible)

Whether guardian angels attend each and every person is not consistently believed or upheld in Christian thought. Saint Ambrose believed that saints lose their guardian angels so that they might have a greater struggle and persevere. Saints Jerome and Basil argued that sin drove the angels away. The first Christian Church theologian to outline a specific scheme for guardian angels was Honorius of Autun (died 1151). He said that every soul was assigned a guardian angel the moment it was put into a body. Thomas Aquinas agreed with this and specified that it was the lowest order of angels who served as guardians, but Duns Scotus said that any angel might accept the mission. The contemporary orthodox belief is that guardian angels protect the body and present prayers to God.

A belief in guardian angels is expressed by the English physician and philosopher Sir Thomas Browne (1605-82) who stated in his Religio Medici first published in (1643):

Therefore for Spirits I am so farre from denying their existence, that I could easily beeleve, that not onley whole Countries, but particular persons have their Tutelary, and Guardian Angels: It is not a new opinion of the Church of Rome, but an old one of Pythagoras and Plato; there is no heresie in it, and if not manifestly defined in Scripiture, yet is it an opinion of a good and wholesome use in the course and actions of a man's life, and would serve as an Hypothesis to salve many doubts, whereof common philosophy affordeth no solution.

Religio Medici part 1 paragraph 33

In the Roman Catholic Church their feast day was originally with that of the angel Michael but is now on October 2.

Guardian Angel Prayer

Angel of God, my guardian dear to whom God's love commits me here.

Ever this day be at my side to light and guard and rule and guide.

Amen.

See also: Holy Guardian Angel Guardian Angel Prayer