How much is a tenth of an Eifah?
Rashi: 1 Eifah = 3 Se'ah; 1 1 Se'ah = 6 Kabin; 1 Kav = 4 Lugin; 1 Log = 6 egg-volumes. Consequently, 1 Eifah = 432 egg-volumes; hence a tenth of an Eifah = 43 1/5 egg-volumes -- which is the Shi'ur for taking Chalah 2 and the Shi'ur of Menachos - Rashi 3 [and the amount that one is permitted to knead on Pesach ? R. Bachye]).
See Torah Temimah, note 58.
Eruvin 83b: This teaches us that the 'dough in the desert' comprised seven Lugin plus one and a fifth egg-volumes.
Gur Aryeh: Rashi deems this relevant here, because if the Torah tells us the exact amount of a daily portion of Manna, it must be due to the Halachos that we will need to derive from it.
Why does the Torah insert this Pasuk here, beginning with the word "and the Omer"?
R. Bachye #1: Refer to 16:16:2:1.
R. Bachye #2: Having discussed the Manna, the Torah now needs to inform us its Shi'ur.
R. Bachye #3: To inform us that, although one only becomes weak in Torah and Avodah as a result of excessive food and tranquility, here Yisrael became weak even though they ate a standard amount of food, which in turn, brought on Amalek, as we are about to see.
Gur Aryeh: With reference to 16:36:1:1 - In order to teach us the Halachos that we can derive from it.
Ba'al ha'Turim: To teach us that, after Moshe's death - on the seventh of Adar - they continued to eat the Manna until they brought the Korban Omer, on the sixteenth of Nisan.
