Oecumenius

And the slander of the illegitimate Jews is interpreted as the confession of Judas. Therefore, the true Jews, and the spiritual Israel, would be those who confess Christ, and Israel are those who see God in spirit. "For the one who is a Jew outwardly is not a Jew, nor is circumcision that is outward in the flesh" pleasing to God, as Paul says, "but the one who is a Jew inwardly, and circumcision is of the heart," not of the flesh. (Rom. 2:28) Therefore, the Jews who have remained in unbelief form a blasphemous synagogue, led by Satan.

Commentary on Revelation ↗

Bede

Those who say they are Jews and are not. They profess to know God, but deny him by their deeds. For Jew is the name of religion. Hence also the Apostle: "For he is not a Jew who is one outwardly, nor is that circumcision which is outward in the flesh; but he is a Jew who is one inwardly, and circumcision is that of the heart, in the spirit, not in the letter."

Commentary on Revelation ↗

Victorinus of Pettau

The following epistle unfolds the mode of life and habit of another order which follows. He proceeds to say:- "I know thy tribulation and thy poverty, but thou art rich." For He knows that with such men there are riches hidden with Him, and that they deny the blasphemy of the Jews, who say that they are Jews and are not; but they are the synagogue of Satan, since they are gathered together by Antichrist; and to them He says:-

Commentary on the Apocalypse of the Blessed John ↗