The Lord provides for our guidance, protection and connection with Himself. It is true, I believe, that there are few aspects of Catholic piety that can be perceived as comfortable to parents as the belief that a guardian angel protects their child from dangers real and imagined. My parents and grandparents taught me the famous prayer to the Guardian Angel.
The guardian angels aren’t just for children. They are not merely the domesticated spiritual figures that Hallmark perpetrates. By definition an angel does what its name means: it delivers a message. The angel has a role: to represent person before God, to watch over them, to aid their prayer and to present the souls to God at death. A Guardian angel is assigned to guide and nurture each human being is a development of Catholic doctrine and piety based on Scripture. The Guardian Angel is not named.
Recall the words of Jesus as recorded in the Gospel of Saint Matthew (18:10) about this doctrine: See that you do not despise one of these little ones, for I say to you that their angels in heaven always look upon the face of my heavenly Father.
Monks and nuns have a tremendous relationship with the angels. In fact, the monastic tradition with angels is based in Scripture and the devotion they had with Divine Presence and God’s promises. Saint Benedict speaks of the angels, e.g. RB 7 & 19, and later the 12th century Cistercian Saint Bernard of Clairvaux, spoke in favor of the guardian angels.
The Church knows a particular feast day, however, in honor of the guardian angels only in the 16th century.