רמב"ם משנה תורה הלכות מתנות עניים פרק ח י פדיון שבויים, קודם לפרנסת עניים ולכסותן; ואין לך מצווה רבה כמו פדיון שבויים: שהשבוי הרי הוא בכלל הרעבים והצמאים, ובכלל הערומים; ועומד בסכנת נפשות. והמעלים עיניו מפדיונו--הרי זה עובר על "לא תאמץ את לבבך, ולא תקפוץ את ידך" (דברים טו,ז), ועל "לא תעמוד על דם רעיך" (ויקרא יט,טז), ועל "לא ירדנו בפרך, לעיניך" (ויקרא כה,נג); וביטל מצות "פתוח תפתח את ידך" (דברים טו,ח; דברים טו,יא), ומצות "וחי אחיך, עימך" (ויקרא כה,לו), "ואהבת לרעיך כמוך" (ויקרא יט,יח), ו"הצל, לקוחים למוות" (משלי כד,יא), והרבה דברים כאלו. ואין לך מצווה רבה כפדיון שבויים.

מסכת גיטין פרק ד ד,ו המוכר את עבדו לגויים, או לחוצה לארץ--יצא בן חורין. אין פודין את השבויים יתר על דמיהן, מפני תיקון העולם. ואין מבריחין את השבויים, מפני תיקון העולם; רבן שמעון בן גמליאל אומר, מפני תקנת שבויים. אין לוקחין ספרים ותפילין ומזוזות מן הגויים יתר על דמיהם, מפני תיקון העולם.

"Captives may not be ransomed for more than their value for the sake of the social order, so that the abductors may not be encouraged to kidnap additional victims. But one may ransom himself using all the means at his disposal. One may also offer a large ransom for a Torah sage, or even if he is not a Torah sage, but just a sharp student with the potential for greatness." Shulchan Aruch Yoreh De’ah 252:4 Rav Yosef Caro

Rabbi Meir of Rothenberg, a 13th century leader of German Jewry, who was held for ransom in a tower in Ensisheim. Citing the Mishnah’s rule that captives may not be ransomed for more than their value, he ordered his community not to ransom him. He died in captivity.

 "The situation in Israel is entirely different [from ordinary pidyon sh’vuyim cases]. The murderous terrorists’ stated purpose is to murder Jews. They hold Jews captive in order to secure the release of a large number of terrorists in exchange for a few Jewish captives. Upon their release, these terrorists reorganize in their efforts to murder Jews and to plan terrorist acts throughout the country…." Rabbi Judah Gershuni, "Pidyon Shevuyim Li-Or Ha-Halakhah"

123 of the Jews who were murdered in the last intifada were victims of terrorists who had been released from Israeli jails.

"[What] value do a hundred degenerate, contemptible terrorists have in comparison to one of our soldiers in captivity, whose life is more precious than a hundred of theirs? How can this exchange be considered ‘more than their value’? Is a terrorist considered of equal value to one of our soldiers? "[Such an] exchange cannot be included in the concept of ‘their value.’ This is particularly true given the tradition in the [Israel Defense Forces] never to abandon even one prisoner of war, and an entire battalion is put at risk to save one prisoner from the enemy. This is the feeling that guides the Israeli soldier who never despairs while in captivity because he is secure in the knowledge that we will come to his rescue at any price. After all, as our emissary, he embarked on a mission to fight to protect our country and to secure our lives. It is as though we made a sacred promise that we will never abandon or forsake him under any circumstances." Rabbi Tanchum Rubinstein, "Shichrur Mechablim Temurat Shevuyim," Torah Sheba’al Peh 31, 1990