Tafsiran Bilangan 28:4: Rashi, Kli Yakar, Rabbeinu Bahya & Siftei Chakhamim

את הכבש אחד THE ONE LAMB [SHALT THOU OFFER IN THE MORNING] — Although it has already been stated in the section beginning with the words ,ואתה תצוה (Exodus 29:38 39): “Now this is what thou shalt offer … [The one lamb thou shalt offer in the morning]”, that was an instruction for the days of the installation ceremony of the priests, but here it states the commands for all generations.

The one lamb you shall offer in the morning. Since it says and the second lamb, it should have said “the first lamb,” and why did it mention the morning burnt offering only once while the offering toward evening it mentioned twice, and you will also find this in the portion of “And you shall command” (Exodus 29:39-41).

את הכבש אחד, “One of the lambs,” we would have expected the Torah to write את הכבש האחד, however the omission of the letter ה here is to alert us to the fact that the word אחד has a numerical value of 13 to teach us that 13 priests were involved in this procedure (Yuma 25). This number is also not accidental but is in itself a reminder that the offering was addressed to the אחד, to the One and Only G’d. In Exodus chapter 29,39 the Torah does write: את הכבש האחד, as is grammatically appropriate when speaking of an animal singled out from its flock as superior.