15 And again he says, Who opposes and exalts himself against all that is called God, or that is worshipped; (against every God; Antichrist forsooth will abhor the idols,) so that he seats himself in the temple of God. What temple then? He means, the Temple of the Jews which has been destroyed. For God forbid that it should be the one in which we are! Why say we this? That we may not be supposed to favour ourselves. For if he comes to the Jews as Christ, and desires to be worshipped by the Jews, he will make great account of the Temple, that he may more completely beguile them; making it supposed that he is the man of the race of David, who shall build up the Temple which was erected by Solomon. And Antichrist will come at the time when there shall not be left one stone upon another in the Temple of the Jews, according to the doom pronounced by our Saviour; for when, either decay of time, or demolition ensuing on pretence of new buildings, or from any other causes, shall have overthrown all the stones, I mean not merely of the outer circuit, but of the inner shrine also, where the Cherubim were, then shall he come with all signs and lying wonders, exalting himself against all idols; at first indeed making a pretence of benevolence, but afterwards displaying his relentless temper, and that chiefly against the Saints of God. For he says, I beheld, and the same horn made war with the saints; and again elsewhere, there shall be a time of trouble, such as never was since there was a nation upon earth, even to that same time. Dreadful is that beast, a mighty dragon, unconquerable by man, ready to devour; concerning whom though we have more things to speak out of the divine Scriptures, yet we will content ourselves at present with thus much, in order to keep within compass.
Source: Catechetical Lectures (New Advent)