But, it cannot be that the rulers have made such a discovery, for we know whence this man is.
We know (οἴδαμεν)
The knowing of the rulers is expressed by ἔγνωσαν; have they ascertained by searching and watching. The people's knowledge, οἴδαμεν, is that of settled conviction.
Referring to His parentage and family.
No one knoweth whence He is
Opinions differ as to the precise reference of these words. Some explain by a popular idea that the Messiah would not be known until anointed by Elias, when he would suddenly appear. Others refer to Isa 53:8; or to Dan 7:13. Meyer says that while the popular belief that the immediate ancestry of the Messiah would be unknown when He came cannot further be historically proved, it is credible, partly from the belief in His divine origin, and partly from the obscurity into which the Davidic family had sunk.