Taanit, Chapter One, Mishnah Four
Our mishnah proceeds chronologically from the last mishnah. There we learned that on either the third or seventh of Marheshvan they add into the Amidah a request for rain. If that prayer has not been answered by the seventeenth of Marheshvan, then a series of progressively more stringent fasts begins.
1) If the seventeenth of Marheshvan came and no rain fell, individuals begin to fast three fasts.
2) They eat and drink after it gets dark and they are permitted to do work, to bathe, to anoint themselves with oil, to wear shoes, and to have marital relations.
Section one: The first set of fasts is not observed by the entire community, but rather only by individuals, probably rabbis and other public figures.
Section two: The lightness of the fasts is expressed in the fact that the night before the fast they can eatthe fast only begins in the morning. Furthermore, the only prohibition that they take upon themselves is eating and drinking. All of the other prohibitions that sometimes apply on fast days do not apply here.
The idea of progressively making the fasts more stringent is an interesting idea. We relate to God as we would to another human being. If we really want something, but it is something that we are going to need frequently, we dont pull out all of the stops immediately.