What is the meaning of "Miher Tzo'ah Lehipase'ach [v'Lo Yamus la'Shachas]"?
Pesachim 118b: Constipation is painful like the day of death (Tzo'eh is like Tzo'ah with an Aleph, excrement).
Bereishis Rabah 21:10: Eliminating normally is a good sign for one who is ill, as long as it is not excessive diarrhea - "v'Lo Yechsar Lachmo."
Rashi and Radak, citing a Midrash: How do you fear man, who dies?. Even in his lifetime, he is very weak. If his bowels are hard (constipated) for him; he must open them, lest he die. Refer to 51:14:3:2. Rashi - Tzo'ah is something that must be emptied, like it says about Mo'av, which the Navi compared to wine - "v'Shoket Al Shemarav v'Lo Hurak mi'Keli El Kli;
What do we learn from v'Lo Yamus la'Shachas"?
Rashi: The one who was handed over to him to be killed, he will not die.
Radak: He will not die in Galus, which is like a grave for him. This discusses the Klal. If individuals die in Galus, they will ascend with Techiyas ha'Mesim.
Targum Yonasan: [Punishments will soon be revealed, but] Tzadikim will not die.
Malbim: Refer to 51:14:1:7.
What do we learn from "v'Lo Yechsar Lachmo"?
Refer to 51:14:1:2.
Rashi: Once he has diarrhea, he must eat much, lest he lack food (in his innards) and die.
Radak #1: Even though he is captive in Galus, he will not lack food. Kel summonses his food for him honorably, among Goyim, their enemies and captors.
Radak #2: When he leaves Galus, he will not lack food on the road - "Lo Yir'avu v'Lo Yitzma'u" (49:10).
Targum Yonasan: Tzadikim will not lack their food.
Malbim: Refer to 51:14:1:7.