What is the definition of "Selav"?
Rashi: It is a fat bird called 'a quail.'
What is the significance of the Selav?
Maharal (Derush Al ha'Torah, p. 20): Like all of their sustenance in the Midbar, it was Ruchani; it transcended the physical. Refer to 16:4:152:1 and its note. 1
Also review our other comments from Maharal on that Pasuk, regarding the Manna.
Why is "Selav" written with the letter 'Sin,' and not with a Samech?
Yoma 75b: Because on the one hand, for the Resha'im, it felt like a thorn (Silon) in their throats, whereas the Tzadikim ate it in tranquility ('b'Shalvah' - pronounced with a Shin). 1
See Torah Temimah, citing the Mechilta - which has a different version of the answer.
How will we reconcile this Pasuk, which writes that a layer of dew fell on top of the Manna, with the Pasuk in Bamidbar 11:9, which describes how the Manna fell on to a layer of dew?
Rashi: In fact, the Manna lay between two layers of dew, as if it was in a box, thereby keeping it fresh.
QUESTIONS ON RASHI
Rashi writes: "Ha'Selav - A type of bird; and it is very fat." Why does Rashi need to specify this?
Gur Aryeh #1: Rashi is explaining the Hey prefix (the definite article) in "ha'Selav" - what is the Selav which we already know of? It must refer to a species that was famous both in prestige and in fat content.
Gur Aryeh #2: Rashi is explaining why Hashem sent specifically this type of meat.