Tim Wright, AP
Scientists fly in a helicopter above the Pu'u O'o vent on Kilauea Volcano on Sunday, March 6, 2011 on The Big Island, Hawaii.

Egypt’s government and economy rested upon the predictable regularity of the unchanging Nile. Its artistic and architectural styles scarcely varied. It seemed as fixed a feature of the ancient world as the landscape itself. Its stable pyramids, built of solid stone, were already 2,000 years old when the prophet Jeremiah was born. Surely, Egypt could be relied upon.

And, confronting the rising Assyro-Babylonian threat, the politicians and people of Judah did trust in Egypt. However, outward appearances notwithstanding, the regime of the pharaohs was not only past its prime but also nearing its end.

“Now on whom dost thou trust, that thou rebellest against me?” demanded the king of Assyria, according to 2 Kings 18:20-21 (compare Isaiah 36:4-6). “Now, behold, thou trustest upon the staff of this bruised reed, even upon Egypt, on which if a man lean, it will go into his hand, and pierce it: so is Pharaoh king of Egypt unto all that trust on him.”

A century later, Jeremiah (46:17) dismissed pharaoh as a mere “noise.” Yet Jeremiah’s countrymen, relying upon Egypt’s support, challenged Babylonian might — and were punished with decades of Babylonian exile. Sitting in even more distant exile and perhaps recalling that catastrophe, Nephi warned against trusting in “the arm of flesh” altogether (see 2 Nephi 4:34).

But if we shouldn’t rely upon fickle, inconstant and often incapable humans, is there solid ground, “terra firma,” upon which we can confidently stand?

Genesis 49:26 speaks of “the everlasting hills,” and similar expressions occur throughout the Hebrew Bible. “Firm as the mountains around us,” we sing (see "Hymns" No. 255, "Carry On"), and when we regard something as absolutely reliable, we say that it’s “solid as a rock.” In our common experience, mountains and the earth seem immovable. But they’re not. Earthquakes unnerve us partly because they put things that shouldn’t move into sudden and unpredictable motion.

Thus, when the Revelation of John, describing the day of judgment, says that “every island fled away, and the mountains were not found” (16:20; compare many similar biblical passages), it predicts a time when, however reliable it may always have seemed, there will be absolutely nothing natural or naturally familiar on which people will be able to rely.

Modern geological science has taught us that not even mountains and islands are constant. Indeed, at every moment they’re either growing or eroding away.

Nowhere is this more apparent than in the Hawaiian Islands. It’s possible to stand on the leading edge of Hawaii, the southern coast of the Big Island, upon land created within living memory. Indeed, at some locations, the creation of new land can be observed on any given day. And, just more than 20 miles offshore, the slowly rising future island of Lo’ihi will reach the ocean’s surface within the next hundred thousand years, and perhaps considerably less. (Scam artists are probably marketing beachfront property on it even as I write.)

In the meantime, Kauai, the oldest island of inhabited Hawaii, is very slowly disappearing. And, beyond Kauai, the holy island of Mokumanamana, sacred to the ancient Polynesians, is already virtually gone, and the former islands of Kure and Midway are now mere coral atolls — as, millions of years from now, barring miracle, Oahu will be.

Where, then, can we place our trust? Is anything stable? The prayerful lyrics of Henry Francis Lyte’s 19th-century hymn suggest an answer: “Change and decay in all around I see;
 O Thou who changest not, abide with me.”

But what does it mean to say that God doesn’t change? It cannot mean that he never alters in any way at all, because he is a person, and varying responses to varying situations are the essence of personality. (An unvarying thing would be more like a rock than a person — but we now understand that even rocks change.) What it means, surely, is that his purposes and character never vary. In scriptural language, he is “faithful.” And, because he has the power to accomplish his purposes and fulfill his promises, we can rely upon him.

The tumult and the shouting dies;

The captains and the kings depart.

Still stands thine ancient sacrifice,

An humble and a contrite heart.

Lord God of Hosts, be with us yet,

Lest we forget, lest we forget.

Far-called, our navies melt away;

On dune and headland sinks the fire.

Lo, all our pomp of yesterday

Is one with Nineveh and Tyre!

Judge of the nations, spare us yet,

Lest we forget, lest we forget.

(See "Hymns" No. 80, "God of Our Fathers, Known of Old")

Daniel Peterson teaches Arabic studies, founded BYU's Middle Eastern Texts Initiative, directs MormonScholarsTestify.org, chairs www.mormoninterpreter.com, blogs daily at www.patheos.com/blogs/danpeterson, and speaks only for himself.