Who says this?
Rashi: Keneses Yisrael says 'I was already stricken many times in Galus.'
What is the meaning of "Garti Meshech"?
Rashi: I lived with Bnei Yefes in the kingdom of Peras, Yavan and Meshech.
Radak #1: I lived in exile a long time.
Radak #2: Meshech is Kedar. They are called so because they are Moshech (draw) the bow. The matter is repeated in different words.
Radak #3: Meshech is a nation from Yefes; it is mentioned in Bereishis 10:2. Yosef ben Guryon says that they are from Bnei Tushkana; they follow the beliefs of the Notzrim. It refers to Romi, which is in the region of Tushkana.
Who dwells in "Ahalei Kedar"?
Radak: They are the families of best lineage among Yishmael; they are the heads of the kingdom. It mentions Galus in Yishmael, but not in Edom, for most of the Galus of Yisrael was among Yishmael.
Malbim: They are wild people, enemies that pain.