According to Reynolds and Sjodahl, the word "Amen," as a substantive, means "truth," as in Isaiah 65:16: "He who blesseth himself in the earth shall bless himself in the God of Truth (Amen); and he that sweareth in the earth shall swear by the God of Truth (Amen)." In the letter which John was directed to write to the bishop in Laodicea, Jesus calls himself, "Amen, the faithful and true witness, the beginning of the creation of God" (Revelation 3:14. See also Revelation 19:11). As part of the Mosaic ritual it was a strong confirmation, as in Numbers 5:22, or Deuteronomy 27:14-26. At the close of a prayer, as in Psalm 106:48, (Compare 1 Corinthians 14:16) it means, "May it so be." Our Lord frequently uses the word as a solemn affirmation, as for instance in John 3:3, "Amen, amen, I say unto thee, Except a man be born again, he cannot see the kingdom of God," where, however, the English version has, "Verily, verily."
The ancient Egyptians had a god, Amen, whom the priest at Thebes endeavored to introduce as superior to Osiris, but not successfully. . . . The name of this divinity is one evidence among many of the close association between the Hebrews and the Egyptians. [George Reynolds and Janne M. Sjodahl, Commentary on the Book of Mormon, Vol. 1, p. 144]
Through the Wilderness to the Promised Land
(1 Nephi )