Why does it say "va'Yaz'ek"?
Radak: He called to me in a great voice.
Malbim: He aroused me to scream loudly and bitterly.
Why does it add "va'Ydaber Elai"?
Malbim: He also spoke words of consolation to me, i.e. "Henichu Es Ruchi..."
What is the significance of going to the north?
Rashi: It is to drive Madai and Paras.
Malbim: Hashem showed to him the evils that will come to Yisrael via them.
What is the meaning of "Henichu Es Ruchi"?
Rashi: They assuaged My anger at Bavel 1 . They killed Belshatzar and Nebuchadnetzar's seed - "Hashem Ahevo Ya'aseh Cheftzo b'Bavel..." (Yeshayah 48:14).
Malbim: They assuaged My anger at Yisrael. I will benefit them in the end, for the Ru'ach of anger subsided.
Radak: I had great anger at Bavel for they harmed Yisrael too much - "Ani Katzafti Me'at v'Hemah Azru l'Ra'ah" (1:15).