The Gentiles ( not spiritual jews/ true Christians) shall tread on Jerusalem until their time is fulfilled – The popes are not christian.
Jerusalem shall be trodden down of the Gentiles, until the times of the Gentiles be fulfilled – http://biblehub.com/luke/21-24.htm
But he is a Jew who is one inwardly; and circumcision is that which is of the heart, by the Spirit, not by the letter; and his praise is not from men, but from God.
Then I heard a holy one speaking, and another holy one said to him, “How long will it take for the vision to be fulfilled–the vision concerning the daily sacrifice, the rebellion that causes desolation, the surrender of the sanctuary and the trampling underfoot of the LORD’s people?”
42 months is 1260 days = 1260 years of papal supremacy.
But exclude the outer court; do not measure it, because it has been given to the Gentiles. They will trample on the holy city for 42 months.