The bicycle analogy of the Atonement, from Stephen Robinson's generally praiseworthy and excellent book,
Believing Christ, has become well known among Latter-day Saints. I've usually just thought of it as a simple way of illustrating one aspect of the mercy of Christ in reaching down to help us overcome our hopeless deficiencies in love (and that's probably how it was intended), but after hearing it read in detail and emphasized in a recent meeting - during one of those moments when I was paying full attention (couldn't help it - the speaker was well prepared and gave an excellent talk) - I became uncomfortable with some aspects of the analogy because of what might be misunderstood.
A friend of mine, Walter Reade (named used with permission) approached me after the meeting and expressed concerns similar to mine. Had the girl had been more industrious or had she found a hundred dollar bill or two, she would have been able to get the bike on her own, with no need for mercy from above. But that is nowhere close to our situation. It's not just that our pennies are numerically short of the price and only get us part way. We are entirely, not just partly, dependent on the Atonement of Christ and His Mercy.
Consider the Resurrection. How much of your body can you resurrect on your own, and how much of it does Christ need to resurrect for you "after all you can do" on your own? Can you handle, say, the legs and the liver on your own, but really need some extra divine help to take care of the spleen, lungs, spine, and cranium? No, we can't resurrect a single particle on our own. It's all grace. (And yes, I recognize that a resurrected body may not have a spleen or liver as we know it.)
So how many of your sins can you erase on your own? Can you gain forgiveness for, say, some mild cursing and a few white lies on your own, but need a little extra help to wipe out the time you flushed your sister's goldfish down the toilet or cheated on your taxes? No, your sins are hopelessly yours, no matter how much fine home teaching you do, no matter how kind you become, unless you accept the gift of grace from the Savior and let Him remove the burden of sin from you.
We have no pennies to contribute to these accounts. The concept of saving up cash and having some kind of difference to be covered is simply inapplicable. We have nothing that can possibly contribute toward the goals of immortality and forgiveness of sin that we seek through the Atonement of Jesus Christ. I fear that people might misunderstand some aspects of the Atonement and our relationship to Christ if they take this popular analogy too seriously or too far. I don't wish to be critical of its outstanding author, but simply wish to note that we need caution in using metaphors. And perhaps we need to rely more heavily on the powerful and beautiful words from the Book of Mormon, which has the most majestic information on the Atonement that you can find, in my opinion.
The bicycle analogy might seem to be consistent with 2 Nephi 25:23, which says that we are saved by grace "after all that we can do." Doesn't that mean that grace makes up the difference after we've done our part?
Walter made a great point in citing 2 Nephi 10:24 to provide some insight into what Nephi probably meant:
Wherefore, my beloved brethren, reconcile yourselves to the will of God, and not to the will of the devil and the flesh; and remember, after ye are reconciled unto God, that it is only in and through the grace of God that ye are saved.
Even after we are reconciled to God, it is still only through the grace of God that we are saved. It's not that we can be saved partially by doing our best to become reconciled with God and live his commandments. Even when we are fully reconciled, that doesn't do it: it's still the grace of Christ that saves us.
Yes, we must follow Christ. The path of accepting Him and His grace in a covenant relationship calls us and leads us to do all we can to follow and obey, to grow and learn. The gift is offered conditionally, but is not earned, not even partly. Our efforts do not save us in the least - His do. (And yes, I agree with the comment posted below that this is consistent with what Stephen Robinson has been teaching about the Atonement. I certainly agree that his writings represent an important contribution in LDS thought and have touched the lives of many people for good.)