I'm going to double-down on my previous conjecture that the "rod of iron" shown in Lehi's dream is more than just a handrail running along a river -- I believe more firmly that we can greatly benefit by seeing the rod as an implement of gathering in the hands of a divine messenger. It is more than just printed words on a page, it is divinely inspired messages, the voice of the Spirit, and invitations to follow the Savior.
A rod is a very apt metaphor for the word of God, a tool used by shepherds to direct their flock. How we choose to respond to the portion of the word we receive is what will ultimately determine our destiny.
Nephi cites Moses and the power of the word
Nephi uses "word" in very clever ways to demonstrate one of the fundamental differences between the faithful and the wicked in 1 Nephi 17. It is very clear by verse 31 that the word of God is much more than just the words he spoke.26 Now ye know that Moses was commanded of the Lord to do that great work; and ye know that by his word the waters of the Red Sea were divided hither and thither, and they passed through on dry ground.
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29 Yea, and ye also know that Moses, by his word according to the power of God which was in him, smote the rock, and there came forth water, that the children of Israel might quench their thirst.
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31 And it came to pass that according to his word he did destroy them; and according to his word he did lead them; and according to his word he did do all things for them; and there was not any thing done save it were by his word. (1 Nephi 17)
Abinadi teaches that hearkening to the word allows us to become "heirs of the kingdom of God"
Abinadi connects hearkening to the words of the prophets with our eternal inheritance.11 Behold I say unto you, that whosoever has heard the words of the prophets, yea, all the holy prophets who have prophesied concerning the coming of the Lord—I say unto you, that all those who have hearkened unto their words, and believed that the Lord would redeem his people, and have looked forward to that day for a remission of their sins, I say unto you, that these are his seed, or they are the heirs of the kingdom of God. (Mosiah 15)
Jesus Christ proclaims the blessings associated with hearkening to the words of the Twelve
Jesus' own words after ordaining twelve disciples and giving them authority to baptize underscore the importance placed on hearkening to the words they are given.1 And it came to pass that when Jesus had spoken these words unto Nephi, and to those who had been called, (now the number of them who had been called, and received power and authority to baptize, was twelve) and behold, he stretched forth his hand unto the multitude, and cried unto them, saying: Blessed are ye if ye shall give heed unto the words of these twelve whom I have chosen from among you to minister unto you, and to be your servants; and unto them I have given power that they may baptize you with water; and after that ye are baptized with water, behold, I will baptize you with fire and with the Holy Ghost; therefore blessed are ye if ye shall believe in me and be baptized, after that ye have seen me and know that I am.
2 And again, more blessed are they who shall believe in your words because that ye shall testify that ye have seen me, and that ye know that I am. Yea, blessed are they who shall believe in your words, and come down into the depths of humility and be baptized, for they shall be visited with fire and with the Holy Ghost, and shall receive a remission of their sins. (3 Nephi 12)
The word of God is the power to change
Mormon teaches this truth when Alma-2 decides to engage in missionary work:
5 And now, as the preaching of the word had a great tendency to lead the people to do that which was just—yea, it had had more powerful effect upon the minds of the people than the sword, or anything else, which had happened unto them—therefore Alma thought it was expedient that they should try the virtue of the word of God. (Alma 31)
The scriptures most certainly contain the word of God, but we should always remember that in times when a living prophet is found on the earth, his teachings will have the power to lead us along the safe path.
Elder Holland said this in General Conference:
Brothers and sisters, in general conference we offer our testimonies in conjunction with other testimonies that will come, because one way or another God will have His voice heard. “I sent you out to testify and warn the people,” the Lord has said to His prophets.
“[And] after your testimony cometh the testimony of earthquakes, … of thunderings, … lightnings, and … tempests, and the voice of the waves of the sea heaving themselves beyond their bounds. …
“And angels shall … [cry] with a loud voice, sounding the trump of God.”
Now, these mortal angels who come to this pulpit have, each in his or her own way, sounded “the trump of God.” Every sermon given is always, by definition, both a testimony of love and a warning, even as nature herself will testify with love and a warning in the last days. (link to source)