Beginning with my mission to Switzerland, I've sometimes encountered a response to Latter-day Saint claims of additional scripture that asks, rhetorically, "We're unable to live up to what we already have in the Bible, so what good would it do us to have more?"

But this seems a pretty flimsy reason for dismissing the possibility, at least, of further revelation.

After all, most of us haven't yet fully mastered even Matthew 5-7, the three chapters of Christ's Sermon on the Mount. (Perhaps, of course, you're an exception.)

In fact, strictly speaking, I can't live up to Matthew 5:48 ("Be ye therefore perfect, even as your Father which is in heaven is perfect"). But this scarcely means that all of the other verses of the Bible, to say nothing of the Book of Mormon, the Doctrine and Covenants, the Pearl of Great Price, and, for that matter, the teachings of modern prophets and apostles, are superfluous.

Nevertheless, Matthew 5:48 remains an extraordinarily important verse. We are, it says, supposed to become "perfect." And this seems to suggest something more than mere (!) moral flawlessness or being error-free.

The Greek word translated into English as "perfect" is "teleoi," which can mean both "initiated"— in that sense, the term was applied to those who had experienced the ancient Greek "mystery" rituals — and "mature" or "fully grown."

I'll concentrate on the second meaning: A related Greek word is "telos," which refers to the natural end, goal or purpose of a thing. Thus, for example, the "telos" of an acorn is to become an oak.

Grammarians speak of "perfect" verbs, which refer to actions that are done, completed, finished. It's in that sense, I think, that we should understand the King James Version's "perfect" at the end of Matthew 5. German translations of the passage commonly use "vollkommen" — which means, roughly, "fully come" — to render it; Arabic translations tend to use "kaamil," which means "complete." We're to become "perfect and entire, wanting nothing" (James 1:4).

It seems to me that the Lord's command in Matthew 5:48 is suggesting that we should strive to grow up so as to be like our Father in heaven. That's our natural "telos." We are to God, potentially at least, as an acorn is to an oak. Which is, when you think about it, a stunningly powerful doctrine.

We are God's "offspring," says the apostle Paul in Acts 17:28-29. He uses the Greek word "genos," which — closely related to our words "genus" and "kin" — can be translated as "offspring," "lineage" or "race." "The Spirit itself beareth witness with our spirit," he also says, "that we are the children of God: And if children, then heirs; heirs of God, and joint-heirs with Christ." (See Romans 8:16-17; compare Galatians 4:7.)

Of course, a quest for perfection can easily lead to discouragement, and, in some cases, even to depression and despair. We're all aware — and if we aren't yet, we'll eventually be made aware, sometimes quite painfully — of how far short of perfection we fall. Fundamental change is slow and often very difficult, and, for some of us, at least, it often seems that we've made distressingly little progress over the years.

But we have time. We have millions of years, if need be. And, even more importantly, we have the atoning grace of the Lord Jesus Christ. When we arrive at the judgment bar of God, we won't be expected to be flawless; we won't be asked to enter heaven on our own merits, as if we could somehow place our Heavenly Father in our debt. If we've accepted the redemptive sacrifice of the Savior, his unique flawlessness will be ascribed to us. "It is by grace that we are saved," testified Nephi, "after all we can do" (2 Nephi 25:23).

In the meantime, while we should absolutely be moving, or at least trying very seriously to move, along the path that leads to perfection, we shouldn't despair at our slow rate of forward travel. "And see that all these things are done in wisdom and order," said King Benjamin, "for it is not requisite that a man should run faster than he has strength. And again, it is expedient that he should be diligent, that thereby he might win the prize; therefore, all things must be done in order" (Mosiah 4:27).

Acorns don't become oaks overnight. Long distance races require … long distances.

Daniel C. Peterson is a professor of Islamic studies and Arabic at BYU, where he also serves as editor in chief of the Middle Eastern Texts Initiative. He is the founder of He blogs daily at