The Book of Mormon begins with Nephi recounting how his father received a vision from God
directing him to warn the people of Jerusalem of pending destruction.
Nephi wanted to know if what his father then said was true,
so Nephi asked God, and he received an answer,
such that he “did believe all the words which had been spoken” by his father.
In describing this experience,
Nephi explained that he had wanted “to know of the mysteries of God”.
But what did he mean by this?
When the word “mysteries” is understood in its ancient context,
it seems likely that Nephi specifically wanted to know the heavenly information his father had learned
directly from the Lord in his vision.
It was well understood in Nephi’s time that a prophetic vision such as the one described by his father
meant that the prophet had been allowed into what is called the “divine council”,
where a prophet would receive his call and learn what he needed to say to the people.
This council’s main purpose was to deliver God’s decrees, written in a heavenly book.
Those decrees were shown and issued to prophets who would, in turn, deliver them to the people.
The divine council and its decrees are referred to in Hebrew as the “sod”.
Because the sod was not available to everyone,
the decrees of the sod were naturally thought to be confidential,
similar to what one might reveal to a close friend.
Because of this, the sod was understood as conveying the mysteries of God, as in Amos 3:7,
“surely the Lord God will do nothing, but he revealeth his secret unto his servants the prophets.”
The word sod was sometimes even translated into Greek as the word mysterion.
Nephi’s statement that he had desired to “know of the mysteries of God”
came soon after Lehi had his experience beholding God seated upon his throne
in the midst of the divine council.
Nephi’s statement thus suggests
that he wanted to know precisely the things that had been decreed in that council:
the mysteries or eternal plan and decrees of God.
Thus, when the Lord visited Nephi and helped him to believe all the words of his father,
the Lord was likely telling Nephi also what had been discussed and decreed in that council.
Because Nephi then could see that what had been discussed in the council
matched the words delivered by Lehi,
Nephi knew that his father was a true prophet
and that he had accurately reported to the people the mysteries decreed in the divine council.
And now you know why.