The following people may take a haircut on Chol Hamoed (since they could not do so beforehand) - One who returned from overseas; a captive or prisoner who was freed during the festival; a person who the Chachamim released from excommunication; a person who had vowed (against taking a haircut, but whose vow was permitted by a Chacham on the festival); a Nazir (who completed his days of Nazirus during the festival); a leper (whose 7th day occurred during the festival, upon which he must shave off all of his hair,).

(Gemara): The Mishnah shows that it is forbidden for anyone else to take a haircut.

R. Simon: The Sages made this decree so that people would not enter the festival unkempt (planning to take a haircut on Chol Hamoed when they have time).

The Mishnah in Maseches Taanis teaches: The men of the Mishmar (group of Kohanim serving that week in the Temple) and men of the Maamad (group of representatives of the people, corresponding to the Mishmar of that week) are forbidden to take a haircut and launder their clothes (during that week). On Thursday of that week, however, they are permitted in honor of Shabbos.

Question: Why were they forbidden on the other days of the week? R. Yosa/ R. Abahu quoting R. Avun quoting Chizkiyah explained - the Sages decreed so that the people would not enter their week of service unkempt.

Beraisa quoting R. Yehudah: One who comes from overseas is prohibited to take a haircut.

R. Yehudah follows his reasoning that it is forbidden for a person to leave the Land of Israel (i.e. to travel merely to increase his wealth).

If so, if a Kohen travelled out of Eretz Yisrael, since he left against the will of the Chachamim, if he returns on Chol Hamoed, he may not take a haircut.

A Kohen once came to R. Chaninah and asked - May I go to Tzur (outside of Eretz Yisrael) in order to perform Yibum or Chalitzah?

R. Chaninah replied: Your brother left and blessed be Hash-m who killed him, and you wish to do the same?!

Some say that R. Chaninah responded as follows - Your brother left the bosom of his mother for the bosom of a strange woman and blessed be Hash-m for killing him, and you wish to do the same?

Shimon bar Ba came before R. Chaninah and said to him - Write for me a letter of honor that I can travel out of Eretz Yisrael to support myself.

R. Chaninah replied: Tomorrow I am going to join your forefathers and they will say to me - We had one dear sapling in the Land of Israel and you permitted him to leave!

The Mishnah had taught: A prisoner who was freed.

It was suggested that this only applies to someone imprisoned by gentiles, but one who was imprisoned by Jews may not take a haircut.

However, this law applies even to a person imprisoned by Jews - a person does not feel content taking a haircut in prison.