Pidyon shvuyim—the ransom of captives פדיון שבויים

Why it stands above the rest. Maimonides explains simply: a captive suffers hunger, thirst, nakedness and mortal danger all at once—that is, in his trouble all other troubles are gathered. Therefore 'there is no greater mitzvah than the ransom of captives' (Laws of Gifts to the Poor 8:10), and money collected for other purposes may be turned to it. One who delays a ransom transgresses not one commandment but several—among them 'do not stand over your neighbour's blood'.

And the limit. The Mishnah (Gittin 4:6): captives are not ransomed above their worth—mipnei tikkun ha-olam, for the good order of the world. The reason is plain: if it is known that any price will be paid for a Jew, Jews will be seized on purpose. Saving one, you doom the next. The same passage says that captives are not helped to escape—for the same reason.

That is, the law here does not waver between pity and calculation: it says both things at once and leaves the weight of the decision with whoever decides.

The case that became the pattern. In 1286 the Maharam of Rothenburg, the foremost rabbi of Germany, was seized and shut in the tower of Ensisheim. The communities gathered enormous sums for him. He forbade the payment—citing exactly this mishnah: if such a sum is paid for him, rabbis will be taken one after another. He sat there seven years and died in captivity. His body was ransomed later; it is told that a man named Alexander Wimpfen ransomed it, asking one reward for himself—to be buried beside him.

How it worked in the communities. Not as an impulse but as a structure: special ransom funds, collections across all the communities of a country, envoys, contracts. The event 'The Four Captives' in this reference work tells how ransomed captives founded the yeshivot of the West; and that is not the only time a ransom changed the course of history.