“While Lehi and his company were still wanderers in the Arabian wilderness, the Lord gave him the promise that he would receive word of the destruction of Jerusalem. (1 Ne. 17:14) Now, after their arrival in America, the Lord gave them a vision in which the fate of that city was revealed.” (Reynolds and Sjodahl, Commentary on the Book of Mormon, vol. 1, p. 232)
It is only by revelation from God that Lehi could know of Jerusalem’s destruction. It is only by revelation that Lehi could know that if his family had stayed in Jerusalem, they would have been destroyed. Many of the rich and wise were killed but many, like Daniel, Hananiah, Mishael, and Azaraiah were preserved by the Babylonians, the king spake unto Ashpenaz…that he should bring certain of the children of Israel, and of the king’s seed, and of the princes; Children in whom was no blemish, but well favoured, and skilful in all wisdom, and cunning in knowledge, and understanding science (Dan 1:3-4). The Lord knew that Lehi would not be preserved as Daniel would be, had he remained in Jerusalem.