In the English language, we recite the Lord's prayer by saying the following words, “Our Father, who art in Heaven, hallowed be thy name.”
Even though we live in the 21st century, Catholics still use the old English word hallow meaning “holy.” It is the same as the word “saint,” which comes from the Latin sanctus.
Most recently the word has become a brand in the Hallow app, which is one of the most downloaded prayer and meditation apps on the app store.
In the context of the Lord's Prayer, our use of the word can be confusing, as it can appear that we are the ones making God's name holy.
The Catechism of the Catholic Church helps clarify this phrase in its section on the Lord's Prayer.
The term "to hallow" is to be understood here not primarily in its causative sense (only God hallows, makes holy), but above all in an evaluative sense: to recognize as holy, to treat in a holy way. And so, in adoration, this invocation is sometimes understood as praise and thanksgiving.
God is the only one who "makes holy," and so our use of the phrase does not mean that we are somehow making God holy, but that we are recognizing his holiness.
We are brought into God's holiness
Furthermore, this phrase has the added intention of bringing ourselves into God's holiness, as the Catechism explains.
But this petition is here taught to us by Jesus as an optative: a petition, a desire, and an expectation in which God and man are involved. Beginning with this first petition to our Father, we are immersed in the innermost mystery of his Godhead and the drama of the salvation of our humanity. Asking the Father that his name be made holy draws us into his plan of loving kindness for the fullness of time, "according to his purpose which he set forth in Christ," that we might "be holy and blameless before him in love."
When we say, "Hallowed be thy name," we are both praising God for his holiness, as well as asking God to bring us into that holiness.
It is a statement as well as a petition that we can meditate on our whole lifetime.