"And they came down and went forth upon the face of the earth; and the first came and stood before my father, and gave unto him a book, and bade him that he should read."
In Lehi's vision Jesus Christ, Himself, gave him a book that held the knowledge of what Jerusalem's sins were. By the power of the Spirit Lehi saw Jesus Christ stand before him and the twelve witnesses standing behind him. They then commanded Lehi to read.
Through following the foot notes we see that this book contained the sins and woes of the land and the iniquities of the people of Jerusalem. Lehi knew their transgressions and by this he would recognize the need to remove his family from the temptations and inevitable destruction of Jerusalem.