Moroni, like many of his prophet-fathers who preceded him, feared that the words he recorded in the Nephite record would be ridiculed and/or rejected by later readers because of his weakness in writing (compare 1 Nephi 19:6; Jacob 4:1; Mormon 8:13-17; Mormon 9:31, 33). We can only speculate as to why these prophets felt that their writing was awkward and weak.
Moroni, like those before him, had earnestly prayed that the Lord would, through the great power of his Spirit, compensate for their weaknesses in writing. In response to Moroni’s prayerful concerns the Lord assured him that the unbelieving, mocking Gentiles could not gain advantage over the meek and humble believers of the Nephite record. Even though the Book of Mormon was written and abridged by mortal men who had mortal frailties and weaknesses the power and Spirit of God transforms this book that fools may perceive as “weak”- as a foolish fantasy- into an inspired volume of scripture that can and does convince Jew and Gentile that Jesus is indeed the Christ.
Although “fools mock” the Book of Mormon, as the word of God it has a “more powerful effect upon the minds of the people than the sword, or anything else” (Alma 31:5), and in this way the Lord’s promise to Moroni is fulfilled as this Nephite record continues to testify of Christ and lead men and women to “the fountain of all righteousness.” See 1 Corinthians 1:25-28.