A foundation is used many times as an example of what we should build on. For example, Ephesians 2:20 states how the Church of Christ is “built upon the foundation of the apostles and prophets,” illustrating how without apostles and prophets the Church would collapse.
However, we need to decide what foundation we need to be built on – Helaman 5:12 and Mormon 5:18 give us our two options (for, ultimately, there are only two options)…
This verse speaks of the “rock of our Redeemer, who is Christ” so that “when the devil shall send forth his mighty winds…” as long as we are firmly built on this foundation of Christ, we shall not be moved! Helaman is speaking to his sons Nephi and Lehi and he assures them that if they build on Christ, they will have “a foundation whereon if men build they cannot fall.”
On the other hand, Mormon tells us what happens if we are not built on the foundation of Christ. He is speaking of the wicked Nephites who are on the verge of extinction because of their iniquities. This is because “they are led about by Satan even as chaff is driven before the wind, or as a vessel is tossed about upon the waves, without sail or anchor…” Without the foundation or anchor of Christ, they are easily led to misery by Satan. And so, as it says in verse 19, the Lord reserves their blessings.
We can see the result of these two groups: Nephi and Lehi did teach “with such great power and authority,” (Helaman 5:18) because of where their foundations lay and, in contrast, the Nephite’s in Mormon’s time were utterly destroyed by the Lamanites.
It reminds me of Christ’s parable of the wise and the foolish man (see Matthew 7:24-27). Whoever follows the teachings of Christ is like the wise man who “built his house upon a rock,” and when the rain came “it fell not: for it was founded upon a rock.” However, the foolish man built his house on the sand…the rains came “and great was the fall of [the house].”