A posuk with Rashi - Chapter 10 verse 12

After the deaths of Nadav and Avihu for serving improperly in the Temple, Moshe directs Aharon and his remaining sons to reestablish the service in spite of the tragedy.

Rashi explains that there is a complex story being told, that is hinted at in the verse itself: “This teaches us that the death penalty was determined for them as well, for the sin of the golden calf [in which they participated].”

In fact, this idea is almost clearly stated in a subsequent verse: (Dvarim 9:20), “Hashem was enraged against Aharon, and considered his destruction.” The Hebrew lehashmid - "to destroy" - refers to the destruction of the offspring; this is a possible interpretation of the verb "to destroy" indicated in the verse "I destroyed his fruit from above" (Amos 2:9).

Moshe prayed for the family of Aharon and succeeded in overturning half the decree; the two older children died, and the younger ones were spared. This is the prayer that is referred to in the verse "and I prayed for Aharon at that time" (Dvarim 9:20).

Looking carefully at the verse, there is no obvious hint to the story that Rashi tells, and the only possible connection is the word hanosarim - "remaining." This verb is much less common than the Hebrew nish’arim, which means the same thing, “the sons who remained.” Rashi is not a devotee of the notion that words are truly synonyms, and often looks for the nuance indicated by the use of the less obvious verb. The meaning of the verb nosar must be different than nish’ar - but this difference is not immediately obvious.

In Breshit 30:36 we learn: "And he put a distance of three days between himself and Yaakov; and Yaakov tended Lavan's remaining flocks". In Hebrew, “hanosaros” - the "remaining" flocks.

Rashi explains: “This refers to the low-grade sheep, the sick and barren ones. They are the ‘leftovers’ which Lavan gave to Yaakov.”

Clearly, Rashi thinks that the verb nosar refers to some part of the group that was distinguished from the larger, original group. In this case, the weak and sick sheep are distinguished from amongst the entire flock, as a subset of the set of sheep.

(Another example might be Samuel 1 15:15.)

In the same manner, our verse refers to the sons who remained as nosarim. They were originally included in the group of Aharon's sons, and for some reason were distinguished and excluded. Once this emphasis is clear, it remains for Rashi to teach us what it was they were originally included in, and what it is that they were excluded from.

Rashi thinks that the bringing of a "foreign fire" by Nadav and Avihu was similar to the building of the golden calf. In both cases, there is no special desire to leave the worship of Gd. But there is transgression, the crossing of a boundary that had been established by Hashem.

The prayers of Moshe determined that there would be a stay of execution for Aharon’s sons, but their final status would be determined by their future actions. Nadav and Avihu proved that the sin of the golden calf had not been eradicated from their desire, whereas the younger sons did not fall into the trap of trying to rebuild the golden calf in the Tabernacle and were therefore saved by the prayers of Moshe.

We remember in this context the verse in Ki Tisa (chapter 32 verse 34): “….and on a day that I make an accounting, I shall bring their sin to account against them.” Rashi explains this verse as follows: “I have heeded Moshe not to destroy them all at once, but whenever I make an accounting of the sins of the people of Yisrael, I will bring a bit of this sin against them with the other sins. There is no punishment in the future which does not include some retribution of the sin of the golden calf.”

The process of atonement exists and generally wipes the slate clean. However, in the case of the golden calf, the people were spared even though they did not deserve atonement. As a result, the case is never closed. Whenever the people indicate that they are being influenced by the golden calf, they are punished for the sin, which was never completely atoned during Moshe's lifetime.

All of Aharon's sons were nosarim - "remaining." Two indicated that they were not able to deal with the inclination to build a golden calf - and were punished as a result.