(Mishnah): An Androginus [is exempt].

Source: "Kol Zechurcha'' exempts an Androginus.

(Mishnah): We are not Mechalel Shabbos for [Bris Milah of] a Safek (viable baby, Safek Nefel) or Androginus. R. Yehudah permits for an Androginus.

Question: What does R. Yehudah say here [about an Androginus regarding Re'iyah]?

Answer: We learn from the following. R. Yochanan ben Dehavai says in the name of R. Yehudah, even a blind person [is exempt from Re'iyah]. One says "even'' only if he agrees to what was said before! (He agrees to all that Chachamim exempt, including Androginus.)

Contradiction: R. Yehudah contradicts himself! There (Re'iyah) he says [that "Kol Zechurcha''] excludes [Androginus], and here (Milah) he says [that "Kol Zachar''] includes [Androginus]!

Answer: R. Yehudah and Rabanan expounded the same verse. Rabanan expound "Arel'' [to exclude a woman, to whom Orlah does not apply]. Why does it say "Zachar''? This requires that he is a total male (without female genitals);

R. Yehudah expounds "Zachar'' [to exclude a woman]. Why does it say "Arel''? This teaches even a partial Arel (i.e. he is not a full male). However, here (Re'iyah, it says only) "Kol Zechurcha'' [to require a total male, and] exclude an Androginus.

(Mishnah): Women [are exempt].

Source: "Kol Zechurcha'' excludes women.

(Mishnah): Slaves [are exempt].

Source: We learn from "Shalosh Pe'amim ba'Shanah Yera'eh Kol Zechurcha [Es Pnei ha'Adon Hash-m]'' - one whose only master is Hash-m. This excludes a slave, who has another master.

(R. Yehoshua ben Levi): What is the source that one who fulfills the Mitzvah of Re'iyah, it is as if he receives the Shechinah? We learn from "Shalosh Pe'amim ba'Shanah Yera'eh Kol Zechurcha Es Pnei ha'Adon Hash-m...''

(Mishnah): A lame person [is exempt].

Source: We learn from "Regalim''.

(Mishnah): A Choleh (sick person, is exempt).

Source: We learn from "v'Samachta''.

(Mishnah): An elder [is exempt].

Source: We learn from "Regalim''.

(R. Yosah): We are lenient about both of these. If he can rejoice, but he cannot walk, we apply to him "Regalim'' [to exempt him]. If he can walk, but he cannot rejoice, we apply to him "v'Samachta'' to exempt him.