What is the meaning of "Ein Chartzubos l'Mosam"?
Rashi #1: It is an expression of confinement, like "Pate'ach Chartzubos Resha" (Yeshayah 58:6). Close the Rasha's fetters in which they tie the poor. Also here, there are no afflictions in their death. They die amidst health.
Rashi (from Shabbos 31b): Chartzubos stands for Charedim and Atzuvim (they are not worried or sad about the day of death.
Rashi #2 (from Shocher Tov): Hashem is not Me'acher (delay) Tzivyonam (their desire). Radak - whatever they desire, He gives to them. A parable for this is a doctor who visited a Choleh. He took his hand, and said to [those around] 'give to him everything that he wants to eat.' Why? [In any case] he will die! So Hashem "u'Meshalem l'Son'av El Panav Leha'avido" (Devarim 7:10).
Radak: They are knots, like "Chartzubos Resha"(Yeshayah 58:6). One who dies amidst pain, it is as if he has knots when life separates, and they are untied only with difficulty. They die in rest, as if there are no knots in their death.
Malbim: Is not found in their natures and bodies a weakness that will hide in holes and hidden places that will bring them to death.
Why does it say "u'Vari Ulam"?
Shabbos 31b: Hashem says, Resha'im's hearts are clear (Maharsha - they expect to have everything nice in this world,) like the opening to the Ulam!' (It is the biggest opening in the Mikdash. It is 40 Amos by 20 Amos.)
Radak #1: They are healthy and strong. Ulam is like "Yesh l'El Yadi" (Bereishis 31:29). In life they are strong, and they die gently.
Radak #2: It is as if it says u'Vari ch'Ulam; the prefix Chaf of comparison is omitted. They are healthy like an Ulam - a strong castle.
