Catechism of the Catholic Church §700 — excerpt
The finger. "It is by the finger of God that [Jesus] cast out demons." If God's law was written on tablets of stone "by the finger of God," then the "letter from Christ" entrusted to the care of the apostles, is written "with the Spirit…
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: LH, Easter Season after Ascension, Hymn at Vespers: digitus paternae dexterae