Catechism of the Catholic Church 350:
Angels are spiritual creatures who glorify God without ceasing and who serve his saving plans for other creatures: “The angels work together for the benefit of us all” (St. Thomas Aquinas, STh I, 114, 3, ad 3).
Prayer for Day 3:
Angel, my guardian, you advise me, you accompany me, you walk with me in the name of God.
God tells me: “If you hearken attentively to his voice and do all that I say, then I will be an enemy to your enemies and an adversary to your adversaries.”
Dear angel, help me to heed your advice and your inspiration, that God might be my protector and always defend and guard me.
Guardian angel entrusted specifically to me, thank you for your constant counsel. Thank you for being beside me along the path of life.
You are a friend, a friend I cannot see, but who I can hear. You are a friend who will be with me in heaven, in eternal joy. Thank you for your friendship and all you do for me.
Thank you, Father, for the gift of my angel.
(Cf. Pope Francis, morning homily, October 2, 2015).
And today we celebrate...