Out of Context

וַיַּעַן אַבְרָהָם וַיֹּאמַר הִנֵּה נָא הוֹאַלְתִּי לְדַבֵּר אֶל אֲדֹנָי וְאָנֹכִי עָפָר וָאֵפֶר - And Abraham answered and said, "Behold now I have commenced to speak to the Lord, although I am dust and ashes."

Rava in Tractate Chulin 88b says that the reward for saying this was that his children would earn the Mitzvah of the ashes of the Para Adumah (Red Heifer) and dust of the Sotah (a woman brought to the Temple accused of adultery was forced to drink a concoction which had dust from the foot of the Altar in it).

Beyond the obvious yet superficial connection of dust/dust, ash/ash, how are Sotah and Para Adumah a relevant reward to Afar v'Efer?

The legendary Dubner Maggid gives a Mashul as only the Dubner Maggid can; there was an upstanding member of society who made a wedding for his son, and all the people and Gedolim were invited. There was the top table for the family, and next to it, another for the Gedolim. The greatest rabbi invited shows up, wishes Mazal Tov, but feels unworthy of sitting in the prescence of the other rabbis, and quietly sits in the corner somewhere. The host feels that the rabbi is not being accorded due respect, and he requested that the whole table of rabbis move to the table in the corner to join this great rabbi. He manipulated the context to make the supposedly unworthy corner into one worthy of having the great rabbi sit there.

This explains the Pshat of the Dubner Maggid, that Hashem took what Avraham said, and changed the context from dust and ash with all their negative connotations, to dust and ash as Mitzvos, the essence of the Torah, the absolute opposite of dust and ash.

A slightly different Pshat was suggested by the Beis HaLevi: Dust of the earth has no past, but tremendous future; it can grow plant life, which itself is alive, can then sustain other life etc, whereas ash has no future whatsoever, but in the past was part of a living thing. Avraham meant Afar V'Efer to be that he had no past, like earth, and and no future, like ash.

Says the Beis HaLevi, Hashem inverted this, by giving the Mitzvah of Sotah, which cleans the woman's past, and Para Adumah which purifies the persons future. Genius, no?

Geshmack !