27 Thus we may see that the Lord is merciful unto all who will, in the sincerity of their hearts, call upon his holy name.28 Yea, thus we see that the gate of heaven is open unto all, even to those who will believe on the name of Jesus Christ, who is the Son of God.
29 Yea, we see that whosoever will may lay hold upon the word of God, which is quick and powerful, which shall divide asunder all the cunning and the snares and the wiles of the devil, and lead the man of Christ in a strait and narrow course across that everlasting gulf of misery which is prepared to engulf the wicked–
30 And land their souls, yea, their immortal souls, at the right hand of God in the kingdom of heaven, to sit down with Abraham, and Isaac, and with Jacob, and with all our holy fathers, to go no more out.”
Mormon places a lot of emphasis here on how sincerity is the key to receiving mercy from the Lord. This fits in well with his description of the sudden and unexpected success of the Church. Many joined in rapid succession, and it was likely that at least some were not sincerely converted. This is a common thread in this part of the Book of Mormon. Rapid growth brings in price which leads to decay. So it is no wonder that Mormon focused on sincerity.
It is also not surprising that be focused on the power of the word of God to cut aside the snares of the devil. This was a period of growing secret combinations. And so Mormon would logically reflect here on the power of God to destroy all the wiles of Satan.
But what is remarkable about Mormon’s sermon and one of the great treasures of the Book of Mormon is his universality and willingness to assume the best about people and their spiritual state. He is confident of the power of God to lead people to salvation. He is sure in his testimony. In light of his life’s experience I find his optimism and faith in God’s grace inspirational.