daf bit: Chagigah 2

Tractate Chagigah begins by talking about the three pilgrimage festivals (chagim). The mishna says all are required to go up to the Temple except (long list here): a deaf man, an imbecile, a minor, a person of unknown sex (a tumtum), a hermaphrodite, women, unfreed slaves, the lame, the blind, the sick, the aged, and one who is unable to go up on foot (from Jerusalem to the Temple). One might be surprised by the exemption for minors, because minor usually means under 13 (or under 12 for girls). What does "minor" mean here? Beit Shammai says: whoever is unable to ride on his father's shoulders and go up from Jerusalem. But Beit Hillel says: whoever is unable to hold his father's hand and walk up from Jerusalem, because it says three regalim. (2a)

"Three regalim" refers to the pilgrimage festivals, but the word is the word for "feet", so we should understand this as "three times on foot". Those who can't go on foot are exempt. (This isn't the reason for all the exemptions, obviously; there's no reason women, slaves, the blind, etc can't walk. We're talking here about the minors.)

(Today's daf is 3.)