Jesus speaks here at the beginning of His career with striking authority, not through a repetition, a simple commentary, or a refinement of the text but as a prophet, one speaking directly the words of God Himself. He knows the text that He is opening for His community perfectly well, since He is permeated with the words of the Old Testament and filled with the Holy Spirit, just like His mother: it will become apparent later in His life that He is not only a special vessel of God's word, He is God's Word. At this early point, though, His mastery of the written word and the oral delivery of it sets Him up for a special role in salvation history.
But then the demon confirms this identity and role of Christ in two ways: it recognizes Jesus as "the Holy One of God" and it is immediately obedient to the authoritative word that Jesus speaks. Jesus immediately gains an even higher standing in the eyes of this synagogue congregation and will move on to teach and heal in even greater ways.
What does that have to do with us? I think that it is very simple: we too must first let the word (Word) of God become the very nourishment of our lives and guide us in every way. We need to study it, pray it, love it, let it be our Law. We also need to constantly pray for the Spirit to bring that word (Word) to active life within us. And, thirdly, we must ourselves speak and act with and in the power and authority of that word (Word), not in a domineering or critical way but by letting our light (God's light) shine in all that we are and do and say, letting our very lives show the presence of God within us, revealing what God actually means to us and how much we have become His servants and handmaidens, how truly we are His children and resemble Him.
And then God will make Himself known to others through us and will Himself cast out the demons that we encounter in ourselves and others.
By Chas Kestermeier