Jerusalem being destroyed in 70ad had a lot to do with prophecy being fulfilled (it took 3 1/2 years btw).
This false doctrine coming in has a lot to do with whether someone thinks there is only one way to be saved or two. There is only one way to be saved, Jesus Christ.
John the Baptist:
Matthew 3:7 But when he saw many of the Pharisees and Sadducees come to his baptism, he said unto them, O generation of vipers, who hath warned you to flee from the wrath to come? 8Bring forth therefore fruits meet for repentance: 9And think not to say within yourselves, We have Abraham to our father: for I say unto you, that God is able of these stones to raise up children unto Abraham. 10And now also the axe is laid unto the root of the trees: therefore every tree which bringeth not forth good fruit is hewn down, and cast into the fire.
11I indeed baptize you with water unto repentance: but he that cometh after me is mightier than I, whose shoes I am not worthy to bear: he shall baptize you with the Holy Ghost, and with fire: 12Whose fan is in his hand, and he will throughly purge his floor, and gather his wheat into the garner; but he will burn up the chaff with unquenchable fire.
And for the support of this Declaration, with a firm reliance on the protection of Divine Providence, we mutually pledge to each other our lives, our fortunes and our sacred honor.