It was taught: The men of the watch would fast every day; on Tuesday they would fast for those who go out on the roads, [because of that which is said on it] “Let the waters under the heaven be gathered.”
On the daf / in context: Continuing the mishmar-fast list: Tuesday’s fast is linked to the gathering of the waters (and the appearance of dry land), relevant to travelers.
Type of Learning: Mishmar fast linked to day of creationWhat Is Learned: The third day’s gathering of the waters is the association for the Tuesday fast on behalf of travelers.