So Jesus is in the synagogue. The Messiah is in a place where prayers were constantly being offered for God to send, well basically, him. Who recognizes Jesus in that synagogue? Not the faithful. The demon.
"What have you to do with us, Jesus of Nazareth? Have you come to destroy us? I know who you are - the Holy One of God!"
What did the demon see that these, probably, very devoted men in the congregation did not see? Let's look at it from another point of view: What "baggage" did the congregation have, that the demon did not, that prevented them from recognizing the Messiah in their presence? Was it a low self esteem that made them think God wouldn't possibly send the messiah to them? Like the gang in the Nazareth synagogue, was it an arrogance that made them believe that the son of Joseph the carpenter could not possibly be what he was claiming to be (namely, that he was the fulfillment of Isaiah's prophecy about God anointing him to bring good news to the poor, etc.)?
That's our task: recognizing Christ. Recognizing him in the Scriptures. Recognizing him in the Eucharist, at Mass and any place we find a tabernacle. Recognizing him in the magisterial teachings of the Church. Recognizing him in his Vicar. He's there whether we believe it or not. The reality of his presence does not depend on us consenting to believe it. How arrogant can we be to think that, if I don't believe it, than it can't be the truth?
How many times have we been someplace (a mall, a street) where our eyes catch glimpses of hundreds of people. Yet if one of those faces we subconsciously scan is a friend, something inside of us goes off, telling us that we "know" this person. Let us ask the Lord to help us to know what to look for in recognizing Him.