The concept of guardian angels, as developed in Catholic theology and piety, has biblical roots. The angel Raphael aids Tobit and his family; one angel interprets for the prophet Zechariah, while another guides Cornelius in Acts of the Apostles; and angels are called “ministering spirits sent to serve” in the Letter to the Hebrews. In Matthew, Jesus teaches: “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.” The Catechism of the Catholic Church says, “Beside each believer stands an angel as protector and shepherd.” Pope Clement X set this date as the feast of guardian angels in the 1670s.