After the tragic deaths of Nadav and Avihu, the Torah records how 'Moshe spoke to Aharon and to Elazar and Isamar, בניו הנותרים — his remaining sons'. (ויקרא י יב)

The emphasis on the obvious — that Elazar and Isamar were now the only children left for Aharon — warrants addressing. (see Rashi)

The highlighting of their being the 'remaining' children appears several verses later when Moshe 'was wrathful with Elazar and Isamar, בניו הנותרים — his remaining sons', for not having partaken from the sin-offering. (שם שם טז)    

Why the already evident and previously stated fact?

The holy Avnei Neizer, the first Rebbe of Sochatchov, suggests that this notion of הנותרים — 'remaining' is synonymous with the word שיריים — leftovers, which the Talmud uses to describe a person who feels inconsequential and unworthy. (מגילה טו:)

They felt inferior to their illustrious brothers, Nadav and Avihu, who despite being punished for having erred are described in the Zohar as being greater than anyone other than Moshe and Aharon. (זח"ג סא ב) 

But why is this detail so significant to be reiterated twice?

Immediately after the first mention of their reticence, Moshe directs them, "Take המנחה הנותרת — the meal-offering that is left from the fire-offerings of Hashem and eat it unleavened near the Altar; for it is the most holy." 

Aharon had earlier apportioned a קומץ — a threefingersful scoop of flour that was burnt on the Altar from this meal-offering. He left behind the הנותרת המנחה — the leftover volume of flour from which it was scooped from, which is now to be consumed by the Kohanim, in this case Aharon, Elazar and Isamar. This is commonly referred to as the 'שיריים' — leftover of the מנחה — the meal-offering.   

Is this נותרים/נותרת =שיריים  parallel merely coincidental?

There is a strikingly similar verse in Megillas Rus, where after reporting how the husband of Naomi, Elimelech, passes away, the verse states, ותשאר היא — and she 'remained', ושני בניה — and her two sons.

The Midrash adding, כשיירי מנחות — like the leftover of the meal-offering.

Several verses later after her two sons die as well, the verse again restates, ותשאר האשה — and the woman was 'left' [bereft] of her two children and of her husband.

The Midrash continues the theme by emphasizing how Naomi is now likened to, שיירי שיריים — leftover from the leftovers.

What are we to do with all these 'leftovers'?

The surviving children of Aharon felt unworthy of the task ahead of them. It was obvious to Moshe, as the Sochatchover pointed out, that they felt inferior and incapable of living up to G-d's expectations from them.

Moshe firmly directs them to take the leftovers of the flour from the meal-offering and consume it near the Altar. The Ibn Ezra indicates that Moshe was alluding to the special role of Kohanim who partakes from the very same offering that is first partially consumed as a fire-offering of Hashem upon the Altar. The leftovers are exclusively eaten by the Kohanim — a testament to their holiness, which effect atonement for the one offering it through their eating it.   

Moshe sought to instill confidence in Elazar and Isamar, by indicating that each one of us has a unique role, no two alike. No one is deficient. Each one of us has the wherewithal to fulfill the Divine mission we are handed. We must not hesitate.

When Moshe takes them to task for seemingly not having followed his directive, he indicated to them that he has full confidence in them and their ability to choose wisely, despite their self-doubt, and wasn't willing to pamper them by giving them any slack.

It was their projecting unworthiness that motivated Moshe to show his full faith in them.

I would boldly suggest, that Naomi is depicted as  שיירי שיריים— leftovers from leftovers — the remaining flour of a meal-offering, to accentuate, not her diminished stature, but on the contrary, her ability, despite what may appear as merely a 'leftover', in becoming the catalyst to generate the Davidic dynasty, that royal family that will beget the Mashiach, and all the hopes of restoring the kingdom of G-d on earth.

There are truly no leftovers. As a wise man once uttered, it's not leftovers that are wasteful, but those who either don't know what to do with them or can't be bothered.

We each have a purpose and are expected to utilize the tools we were each given suited to our specific mission and abilities to infuse all our actions with inspired meaning, promoting solely the will of Hashem.

באהבה,

צבי יהודה טייכמאן