The meaning here is that the Jews claim that the Prophets Ibrahim, Ismail, Ishaq and Yaqub u were all Jews or Christians, so say to them, Oh Muhammad, “Are you more knowledgeable or is Allah?” and there is no doubt at all that Allah U is more knowledgeable! These words are about the Jews, as the Torah had precise details on the description of the Prophet r and glad tidings of his message and his coming. However, the Jews concealed these and their witnessing of the truth and denied all of it when the seal of the Prophets r appeared being of a race other than theirs, that is, not a Jew and not from the line of Yaqub and Ishaq. Hence, they concealed what was in their book on the traits and characteristics of the Prophet r.
There is not a person who does more wrong that one who hides what Allah has revealed in His books and Allah, is not unaware of the truth of what they do.