What was in the letters?
Malbim: The king's command; they read the letters aloud to the people.
Why did he say "v'Yashov El ha'Peleitah ha'Nish'eres Lachem mi'Kaf Malchei Ashur"?
'Rashi': Even though Melech Ashur did not yet exile them, they considered it as if he already did. Also, Melech Ashur already seized everything in the days of Achaz. They considered it as if they were exiled, since for six years they were slaves to him. They gave gifts to him, and he exiled them and did to them as he wanted. This episode was during the six years. They were already exiled several times in the days of Malchei Yisrael and Achaz. They knew that once Yisrael rebels, he will take them to Galus. Yehudah was called ha'Peleitah (remnant), because Melech Ashur did not rule over it.
