Scriptural analysis: It is interesting that the referent for the pronoun "he" is the God of Israel in verse 7. Rather than assume that Nephi might have confused the Savior with God the Father, we should remember that this is the very role that the Savior performed as Jehovah.
Historical analysis: The six hundred year prediction is the basis for most Book of Mormon dating, but is complicated by two factors. The first is the possibility that the angel was "rounding off," and that for prophecy there is little pragmatic difference between 600 years and 601 years (or 602, etc.). The second problem is that we can use the 600 years from Christ's birth, but we are then embroiled in the general controversies over that date. The current consensus would place Christ's birth at 4BC in our current calendar, based on the scriptural requirement that Harod be alive when Christ was born, and the historical information that Herod died in 4BC.
Even without dating to the precise year, it is important to realize that the general timing of the events of the Book of Mormon do fit with the known chronology of the Old World, up to the time of their departure. Dating events in the New World is much more problematic as we do not know which calendar the Nephites used, and we do know that while the Mesoamerican calendric system was fairly standard, the specifics of dates for different cultures could vary. From this point on in the Book of Mormon, chronology is a guesswork affair, bounded by this general marker of 600 years. Because the Book of Mormon does note Christ's birth, the early dates, and those near the birth of Christ have a reasonable chance of being fixed in time. Other dates are relative to those.
John Sorenson suggests another interesting possibility of correlating the Book of Mormon timetable with that of the Old World:
"Both by prophecy (1 Nephi 10:4; 19:8; 2 Nephi 25:19) and by Nephite historical reckoning (3 Nephi 1:1), the American scripture allots "600 years" for the interval between Lehi's departure in Zedekiah's first year and the birth of Jesus Christ. Yet secular historical records allow no more than about 593 years (597 B.C. to 4 B.C.) between these events. Although there appears to be a problem, an interesting solution exists. To grasp it we must suppose that Nephite time-keeping would have followed the principles of the calendar that was widespread in southern Mesoamerica in the time and place that the scriptural account was written. All the material in this book to this point supports that important relationship.
Note that the word "year" has several meanings in different civilizations. Va44rious definitions of "years" are recognized, each used for a different purpose. An unabridged English language dictionary reveals that even we have several different counts for which we use the one word. Among the lowland Maya, whose calendar is the one we know best in southern Mesoamerica, at least three kinds of "years" were calculated: (1) the tzolkin or sacred year of 260 days (thirteen months of twenty days each), (2) the haab, which was 365 days long (eighteen months of twenty days each, plus a closing "month" or five "unlucky" days), (3) the tun of 360 days. The tun was used for most calendrical calculations, apparently serving as an approximation to the haab, having the special merit that it could be divided and multiplied far more conveniently (360 is divisible by many numbers, 365 by very few). The Mayan calendar specialists loved to "play around" with dates that went ahead millions of years and back as far as 400 million years! The Mayan counting system adapted to calendrical matters, then, went like this:
1 day = 1 kin
20 days = 1 minal ("month")
360 days = 1 tun ("year")
20 tuns = 1 katun
20 katuns= baktun ("cycle")
Let us not suppose that this recognition of several types of "year" units indicates any confusion on the part of the ancients about astronomical realities. The experts in the Mesoamerican societies knew with great precision how long it took the earth to go around the sun and how this cycle correlated with the moon in its motions, with Venus and Saturn cycles, and no doubt with other information on the heavenly bodies (in the Book of Mormon, compare Alma 30:44; Helaman 12:14-15). Use of the 360-day tun year was a conscious compromise of convenience, no more. Suppose the Nephites used the same system of counting time as the Maya. The prophesied "six hundred years" in that reckoning would constitute precisely one and one half baktuns (thirty katuns), a neat total of 216,000 days. But this count of 600 tun "years" would be about 3,156 days shorter than the total using our sidereal year today (approximately 365 days, 6 hours, 9 minutes, and 9.54 seconds long). In other words, "600 years" by the Maya tun method of calculating time would turn out 8.64 years shorter than "600 years" in today's conventional sense. If we mark off 600 tun years from Zedekiah's first year, 597-596 B.C., 216,000 days brings us into the year overlapping 5-4 B.C., an acceptable date for Christ's birth. (Sorenson, John L. "AN ANCIENT AMERICAN SETTING FOR THE BOOK OF MORMON, Deseret Book 1985, p. 272-3).