What Book of Mormon prophet predicted in 6 BCE that Jesus would be born in five years and that the night before he was born would be as bright as day?

Samuel the Lamanite

Behold, I give unto you a sign; for five years more cometh, and behold, then cometh the Son of God to redeem all those who shall believe on his name.

And behold, this will I give unto you for a sign at the time of his coming; for behold, there shall be great lights in heaven, insomuch that in the night before he cometh there shall be no darkness, insomuch that it shall appear unto man as if it was day. Helaman 14:2-3