The "finger" of God is an interesting thought and study. Exodus 8:19, & 31:18 speak of the tables of the law given to Moses which were "written by the finger of God". Deuteronomy 9:10 repeats this fact for us.
When Jesus was questioned and challenged by many concerning His power over demons and devils; He said that He cast them forth with "the finger of God". Luke 11:20
Now, consider that Peter teaches us also that prophesy came in Old Testament times, not by the whims and imaginations of men, but by the Holy Ghost's moving upon men. Thus the interpretation is not left to men, even those that spake it, but God who sent and gave it. 2 Peter 1:20,21
Now to verify a thought: God is sovereign in all His ways and doings. That is a clear and established fact in scripture. He does not need men to accomplish His purposes. He can speak and create. The power of His voice can take hold of demons and cast them forth or move mountains as He so chooses.
And yet, He used Moses to teach the law. He used prophets to speak. He came in person and taught, fulfilled, and finished this work in the man, Jesus Christ. He remains the power of the word today in the manner He has chosen to manifest His power in the Church, preaching.
God does not need men, but there is no reasonable doubt that He uses men to preach. What a sobering thought to be touched by the "Finger" of God and moved to proclaim His truth today. Oh God, may it be so. Not to be cut to the heart, but pricked. The power and authority is not the man, but the "Finger" that moves him. Amen.