Charles Ellicott Commentary Luke 11:20

"But if I by the finger of God cast out demons, then is the kingdom of God come upon you." — Luke 11:20 (ASV)

If I with the finger of God . . .—Note the substitution of this language for by the Spirit of God, in Matthew 12:28, and its connection with the use by the older prophets of the hand of the Lord, to indicate the state which issued in prophetic inspiration (Ezekiel 1:3; Ezekiel 37:1), and with the finger of God as writing the Commandments on the tables of stone (Exodus 31:18), and Pharaoh’s confession that the finger of God was with Moses and Aaron in the wonders which they performed (Exodus 8:19).

The meaning of this boldly anthropomorphic language is sufficiently obvious. As the “hand” denotes power generally, so the “finger” symbolises power in its concentrated and specially-directed energy.