Pesachim 87b: Hashem exiled Yisrael to Bavel only because it is as deep as She'ol (Gehinom) [from which He promised to redeem them].

Yevamos 17a: From She'ol I will redeem them, and from death" - but there is no remedy for Pesulim of Herpanya (a place of poor lineage).

Rashi: I would have redeemed them from She'ol and from death, but now (refer to 13:14:2:1).

Radak: I would redeem them from She'ol if they were Chachamim. The matter is repeated in different words. - "mi'Maves Eg'alem."

Malbim: Then was time to be born. I intended to redeem them from She'ol, that they would repent amidst many afflictions and birth contractions, and redeem them from Melech Ashur, and from death. She'ol is a Mashal for Galus. Hashem intended to save them from Galus, and from many that Melech Ashur killed. However, they did not repent.

Rashi: I will set Myself to speak words of death about you.

Radak #1: Now that he is not Chacham, rather, base and denies My good, not only will I not redeem him from death - I will bring death upon him via Dever, the sword, hunger and evil Chayos. "Devarecha" are words that I sent to you, and you did not heed My voice. It will cause death to you. "Devarecha" is like Devarai - the pronoun can refer to the object (for who the words are) or the subject (the One who spoke them). Similarly, "v'Simachtim b'Veis Tefilasi", "Shamati Es Tefilasecha" (Yeshayah 56:7, 38:5).

Radak #2: Devarecha is like Dever (plague), for it is next to "Katavcha" - "mi'Dever ba'Ofel Yahaloch mi'Ketev Yashud Tzaharayim" (Tehilim 91:6).

Radak citing Targum Yonasan: My word will be among you to kill...

Malbim: This addresses death (it is personified). Not only did I not redeem [Yisrael] from your hands - I will be your Dever - your Shali'ach to kill.

Rashi: I will put upon you the decree of She'ol.

Radak: I will cause you to be cut off to She'ol. Katav is cutting. The same applies to "mi'Ketev Yashud Tzaharayim" (Tehilim 91:6). Targum Yerushalmi of "Lachtov Etzim" (Devarim 19:5) is Lemiktav A'in.

Malbim: This addresses She'ol. You use Ketev Merari to eradicate people - I will be your Shali'ach to exile them. Not only will I not redeem them, since they did not repent - rather, I will eradicate them with death and exile from their land with My Hashgachah. I will help this occur!

Rashi: I will not retract from this evil. Nochem is an expression of retraction. The Mem is from the root, like No'am, for the penultimate syllable is accented, and the Ches has a Patach. If it were an expression of Nach, and the Mem were a plural pronoun, the last syllable would be accented, and there would be a Kamatz under the Ches, like Rucham.

Malbim: Regret is always the reason to retract a harsh decree. When the nation regrets their deeds and repents, Hashem retracts the evil that He said to do. Now I do not see regret in the nation, so I will not regret the evil that I decreed.