Charles Spurgeon Commentary John 7:26-27

"And lo, he speaketh openly, and they say nothing unto him. Can it be that the rulers indeed know that this is the Christ? Howbeit we know this man whence he is: but when the Christ cometh, no one knoweth whence he is." — John 7:26-27 (ASV)

They had a notion—perhaps derived from that passage in Isaiah, who shall declare his generation?—that the birth of Christ would be hidden in mystery. At any rate, there was some cloudy idea floating about that it would be concealed.