What slaves were on horses?
Rashi: The Kasdim (of Bavel) - "Zeh ha'Am Lo Hayah" (Yeshayah 23:13). They ascended to be on horses, leading Bnei Yisrael captive in chains.
Ibn Ezra: "Yesh" (5) applies also to this; it happens sporadically.
Rashbam: This explains "Nitan ha'Sechel" (6). The slaves act like masters and officers, and ride on horses.
Rid: Slaves who rose to grandeur.
Seforno: A foolish king elevates the lowly.
What is the significance of officers going on the ground like slaves?
Rashi: [Officers of Yisrael] went in front of the wagons of the Kasdim.
Rashbam: They did not ride on horses; the elevated are below, and the lowly are on top.
Rid: Officers who descended from their grandeur. All this is "ki'Shegagah she'Yotza mi'Lifnei ha'Shalit" (5); it is improper.
Seforno: A foolish king lowers the officers and esteemed of the nation.
Metzudas David: It is proper for slaves to walk by foot.
