Memorial of the Holy Guardian Angels

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" - Matthew 18:10

Each person on earth has a guardian angel who watches over them and helps them to attain salvation. It has been a common theological opinion that this angelical guardianship begins at the moment of birth; prior to this, the child would be protected by the mother's guardian angel. But this is not certain, and since we now know that the soul is infused at the moment of conception, it may be that the angelic guardianship also begins at that moment. In any case, this protection continues throughout our whole life and ceases only when our probation on earth ends, namely, at the moment of death. Our guardian angel accompanies our soul to purgatory or heaven, and becomes our coheir in the heavenly kingdom.

Readings

Holy Mass

Prayer to one's Guardian Angel
The Angel of God (Angele Dei) Prayer
Angel of God, my guardian dear,
 to whom God's love commits me here,
 ever this day (or night), be at my side,
 to light and guard,
 to rule and guide. 
 Amen.