1 Nephi 1:1. Mysteries of God
The words “the mysteries of God” in 1 Nephi 1:1 were taken from 1 Corinthians 4:1, which, being in the New Testament, was unavailable to the Nephites, who left Jerusalem six centuries before Christ’s birth.
In the KJV Bible, the word “mystery” appears only in the New Testament. This is because different parts of that Bible were translated by different individuals and committees, and the Old Testament translators chose to use the word “secret,” while the translator(s) of 1 Corinthians chose to use the word “mystery.” The term “secret of God” appears in Job 15:8; 29:4.