Textual: By the time Mormon wrote these passages he had already read the small plates of Nephi that he appended to his record (Words of Mormon 1:3). Since he had read them, it is tempting to see his vision of his own people as having been colored by a passage for the first Nephi:
2 Nephi 26:11
11 For the Spirit of the Lord will not always strive with man. And when the Spirit ceaseth to strive with man then cometh speedy destruction, and this grieveth my soul.
Nephi indicates that there will come a time when the opportunities for repentance are passed, that the Spirit itself will no longer strive to redeem mankind. Significantly, Nephi ties this loss of the Spirit to speedy destruction. Mormon saw the loss of the Spirit in the people, and notes that “the day of grace was passed with them, both temporally and spiritually.” In other words, they were in that condition described by Nephi where the Spirit would cease to strive with man. Mormon understood, painfully understood, that he was now witnessing their “speedy destruction.”
For Mormon this is a physical and immediate destruction as well as a spiritual and future destruction of their soul. These compatriots were dying from their combat. After that death their souls would also lose the battle with Satan, and become his – at least in this metaphor.
Is it true that the Spirit will cease to strive with man? This would appear to violate the longsuffering of the Lord. The key to this is that it is not the Spirit who voluntarily withdraws, but that the hearts of men become so hardened that he is no longer able to penetrate to that soft part of the heart that might hear. With no access to the tenderness of true repentance, the Spirit withdraws because we no longer admit him, not because he tires of the attempt.