What is the meaning of "v'Anah Ge'on Yisrael"?
Rashi citing Targum Yonasan: The honor of Yisrael was lowered. This is like "Me'anta Le'anos" (Shemos 10:3) ? poverty and submissiveness.
Rashi citing Dunash: This is an expression of testimony. When their punishment comes, they testify about their pride ? they transgressed My will. Radak - this is like "Hoy Ateres Ge'us Shikorei Efrayim" (Yeshayah 28:1).
Malbim: This is when his pride will be humbled, and he will sense that he is receiving punishment for his deeds. When they will stumble and fall, they will know that it is due to their sin.
Why does it say "b'Fanav"?
Rashi citing Targum Yonasan: V'Inun Chazan. Radak ? when they are in their land, before they will be exiled, they will see their submissiveness and lowliness in place of the honor that they had initially.
Why does it say "v'Yisrael v'Efrayim"?
Radak: It says Efrayim due to Yaravam ben Nevat, who made them stray; he was from Shevet Efrayim. It says Yisrael due to the rest of Yisrael, who went after him; all stumbled in the sin of the calves.
How did Yehudah stumble with them?
Radak: Even Yehudah, that the Beis ha'Mikdash was in their portion, they abandoned Avodas Hashem to serve other gods.