Be careful that you do not forsake the Levi, all your years on the Land.
Be’er Mayim Chaim: The Torah repeats this warning several times. Much can be said on different levels to explain the repetition. In the context of our parshah, we can offer one approach here, treating it as an allusion to an important topic that is not obvious in the plain peshat of the pasuk.
Moshe will soon tell his people, “Take heed and listen, Yisrael! Today you have become a nation for Hashem your G-d.” Today? Did not receiving the Torah at Sinai almost forty years prior turn them into a nation? Didn’t Hashem Himself say that it would when He told Moshe at the very beginning of his career, “I will take them out…I will redeem them, I will take them to Me as a people…” What could there have been about the particular day Moshe addressed the people just before his death? How was that day recast as the beginning of nationhood?
The answer has much to do with the power of a single moment.
Within the concept of gilgul resides a well-publicized principle regarding the need for a neshamah to return. Many understand gilgul as another opportunity given to a person to accomplish what he failed to do in a previous life. This teaching includes situations that would raise some eyebrows. A person may have performed all the affirmative mitzvos expected of him in his sojourn on earth, and likewise avoided all the prohibitions placed before him, and still be required to return to this world as a reincarnation. This may happen if a single mitzvah in the course of his lifetime remains missing from his inventory. Without knowing it, that item was prominent on his spiritual bucket list. Similarly, a single aveirah in his life may turn out to be a deficiency so great that he will need to return to somehow undo the damage he caused. In other cases, a person who leaves this life deficient in no area may be chosen to return in order to be available as a single moment when his intervention will be needed on behalf of others.
In all these cases, it is somehow adjudged in the Heavenly Court to send a neshamah to this world which will need to be sustained for decades, will interact with countless people, will marry and father children – all for the purpose of a single moment in his new life. (Indeed, we can treat this as another aspect of Chazal’s maxim “Some acquire their [eternal] world in a single instant.”)
Taking this possibility into account sobers us. We know from experience that the yetzer hora opposes us in all attempts to do good, and never relents in attempting to ensnare us in aveirah. When an opportunity to perform a mitzvah (or avoid an aveirah) is so important that an entire lifetime revolves around it, the resistance of the yetzer hora is extraordinary.
At times, we sense repeated obstacles and obstructions on the way to accomplishing some good. After a while, many of us give up. It should cross our minds, however, that there is at least a possibility that the numerous roadblocks were placed there by an energized yetzer hora intent on blocking us from rising to what might be the defining moment of our lifetime. We should resist the yetzer hora with the same determination that it wages war against us.
Perhaps this is part of what Moshe wished to convey in saying, “Take heed and listen… Today you have become a nation.” He meant to tell them that although in their minds, they had become a nation decades ago, their election to this position might have been conditioned on future performance. And each day might present such a challenge. Every day might be the “today” regarding which so much history has been predicated.
And this may also be part of the larger meaning of the pasuk which launched our discussion. The word levi comes from the word “accompany.” (Leah used it for her third child, to signify that in her quest for the affections of her husband, providing a third son to him would certainly mean that he would now accompany her, walking side by side with her through life.) We must be constantly vigilant about the item that may define the value of our entire existence, which accompanies us as our life’s mission – even when we are not be aware of it.
Understanding the value of a single decision, a single action, a single moment of life, can make all the difference in the worlds – this, and the next.
 Based on Be’er Mayim Chaim, Devarim 12:19
 Devarim 27:9
 Avodah Zarah 17A