Why does the Torah insert the Parshah of wine here?
Seforno: Refer to 10:1:1:2*.
What is the meaning of "Yayin ve'Sheichar Al Teisht"?
Rashi and Ramban #1: It means that a Kohen may not drink wine in a manner that intoxicates 1 before performing the Avodah.
Ramban #2 (citing Rambam): It means wine and beer (incorporating all intoxicating drinks).
The Pasuk only prohibits drinking wine before entering the Heichal. What if he drinks wine before approaching the Mizbe'ach in the Azarah?
Rashi and Ramban (citing the Toras Kohanim): We learn it from washing one's hands and feet, 1 where the Torah places on a par approaching the Mizbe'ach to entering the Heichal; the same applies here.
With a Gezeirah Shavah 'Bi'as Ohel Mo'ed' from 'Bi'as Ohel Mo'ed' (Rashi).
What exactly does the Isur of entering the Ohel Mo'ed or approaching the Mizbe'ach entail?
Though according to the Rambam, it is only the Chiyuv Misah that requires performing the Avodah; the La'av applies even the moment the Kohen approaches the Mizbe'ach or enters the Heichal (Ramban).