Explanation: Since we learn a Gezeirah Shavah from Meshares, we should say that it is like Meshares. A Meshares may not be a Ba'al Mum. Also Mevarech...

The Gemara answered that he is equated to a Nazir...

Inference #1: A Ba'al Mum may give Birkas Kohanim. We see that the Gemara wanted to learn Mevarech from Meshares, regarding a Ba'al Mum, and rejected this. If so, a Ba'al Mum Kohen may give Birkas Kohanim.

Inference #2: A Kohen who became an apostate may give Birkas Kohanim. He is Kosher for Birkas Kohanim and Keri'as ha'Torah, just like one who did not became an apostate.

Proof: We find that Kohanim who served in Beis Chonyo may not serve in the Mikdash, but they receive a share [of Kodshim] with their brothers, like Ba'alei Mumim;

Inference: Since it says that they are like Ba'alei Mumim, this connotes that everything proper for a Ba'al Mum to do, they may do. A Kohen Ba'al Mum may give Birkas Kohanim.

Explanation: The Gemara asked "why do you equate a Kohen to a Nazir to be lenient, and say that just like a Nazir Ba'al Mum [is a full Nazir], a Kohen Ba'al Mum is Kosher [for Birkas Kohanim]?"

You [also] equate [Birkas Kohanim] to a serving Kohen. Just like a serving Kohen may eat Chartzanim (grape pits or peels), a Kohen who will bless may eat Chartzanim.

Why not equate them to be stringent? I.e. say that just like a Nazir may not eat Chartzan, a Kohen may not eat Chartzan. Just like a Kohen Ba'al Mum may not serve, a Kohen Ba'al Mum may not bless!

The answer: The Gemara answers that it is a mere Asmachta...

Explanation: Therefore, everyone is Kosher to say Shirah, even Pesulim and Mamzerim, since it is only vocal;

According to the opinion that Shirah is primarily instrumental, we require Kohanim or Leviyim, for the instrument was Kodesh.

Explanation: The first one reads three verses from the Parshah, and the second, who has only two verses, skips [backwards] one verse and reads what the first one read [and two new verses];

Similarly, on Rosh Chodesh we skip (repeat).

Question (Rabbeinu Yehudah bar Nasan): Why do we skip? Why don't we read above in the Parshah?

On Shabbos Chol ha'Mo'ed, we read from "Re'eh Atah Omer Elai...", even though the essence of the Parshah begins only from "Pesal Lecha"!

Answer: He reads "Re'eh" in the Parshah above, because the entire Parshah discusses one matter. However, the Parshah of Rosh Chodesh (the Tamid and Korbanos Musaf), above it does not discuss at all the same matter!

Therefore, we do not read from the previous Parshah. Rather, he skips.

Support: This supports our custom, that we do not read on every Shabbos [for Maftir] the Parshah of Korbanos [Musaf] Shabbos, [un]like on Yom Tov, when we read the Parshah (Musaf) for that day;

This is because the Parshah of [Musaf] Shabbos does not have three verses. We do not say that we should skip [and start] above, for it is not the same matter.

Explanation: Those who enter did not see the previous ones read three verses. If they see the second (i.e. the first after they entered) read one verse above, they will say that the first (the one before him) read only two verses (the rest of the Parshah above);

Those who leave, if they would see the first (or anyone before the last) read three verses, and leave only two [in the Parshah], we decree lest they reason that it will suffice for the second (the one after him) to read [the] two [remaining] verses.