Rashi: Those mentioned will not lie with Giborim who died their own (natural) death. They will fall [to the sword], and are inferior to those who died naturally, and descend to the grave with their weapons.

Radak: Until their death, they held their weapons. It is as if they put their swords under their heads when they lie in the grave. I.e. until the grave, they overpowered in war.

Malbim: Kings of Goyim consider it honorable that their Giborim fell in war holding their weapons.

Rashi: This is a sign ¹ that [another's] sword did not rule over (kill) them.

Radak: Refer to 32:27:2:1.

Malbim: They will lie together with their enemies, the Yishmaelim ² .

Rashi: Nothing was detracted from their sins. Death via the sword did not atone for them; they were not killed.

Radak: The punishment for their sins was on their bones ? they were stabbed, and their bones were broken.

Sha'arei Teshuvah 4:13: When Musar (punishments) come upon Hashem's enemies, they die for one sin, and the rest of their sins remain on them.

Malbim: They will not get Kaparah via their flesh being finished (decayed); their sin will remain on their bones, which remain after the flesh is finished.

Rashi: This was their sin [Malbim ? for which they were punished. Radak ? i.e. why they will not die a natural death].