Mormon's final admonition echoes Nephi's, and the doctrine of Christ. Repent, be baptized with fire and water, "lay hold upon the gospel of Christ" and follow "the example of our Savior." Doing what we've seen the Lord do is equivalent to standing in the strait and narrow path and speaking with the tongues of angels in 2 Nephi 31-32. 3 Nephi 27 shows us that the "gospel" is the same thing as the "rock."
So Mormon, at the end, tells us to repent, be baptized, receive the Holy Ghost, and approach the Lord in his temple.