In these two verses we learn that Lehi told the people of Jerusalem three things. First, he told them of their wickedness and abominations. Secondly he told them that unless they repented Jerusalem would be completely destroyed just like Jeremiah said it would. And third, Lehi told the people of Jerusalem something that was absolutely forbidden among the Jews. He said that when their Messiah came among them they would not recognize him but denounce him as an imposter and kill him.
The Jews believed this prediction was a wicked myth and that it threatened their very integrity as a people. They would never kill their Messiah. In fact, years earlier when prophets had made this prediction it was decided that they would kill anyone who taught this terrible doctrine. They had stoned Zenos to death for teaching this doctrine, and also Zenoch. And now when they heard Lehi saying that he had seen a vision of the future and they would kill their Messiah there was an uproar among the people. Here is what happened.