Rashi #1: When a lion holds prey, he roars. He roars only if he captured ? "Yish'ag ka'Kefirim v'Yinham v'Yochez Teref", "Ka'asher Yehgeh ha'Arye veha'Kefir Al Tarfo" (Yeshayah 5:29, 31:4). Our verse refers to Nebuchadnetzar.

Rashi #2: The Nevi'im compare Ru'ach ha'Kodesh that comes upon them to the roaring of a lion, like it says below "Arye Sha'ag Mi Lo Yira" (8). Here it did not explain the Nimshal. Ru'ach ha'Kodesh does not come to predict evil that will come unless it was decreed in front of Him ? this is the Teref.

Radak: This is a Mashal. A lion will not roar in the forest and not get prey, for when animals hear it, they stand in their place due to fear of it, and it tears from them as it wants. Similarly, when the enemy comes against you, he will not return empty without killing or taking captives from you.

Radak citing Ibn Ezra: Does a lion roar only when it has prey, and I roared for nothing?!

Malbim: The second introduction is, when a lion roars in the forest, surely it has prey. It would not roar for nothing. Verse 12 refers to Melech Ashur. He will roar at them, tear people and eat, and no one can save from him.

Rashi: Hashem would not give His voice to speak harshly, unless you were caught in the trap of sin.

Radak: The matter is repeated in different words.

Radak citing Ibn Ezra: Did you see a lion rise from his den and give his voice (roar) over his prey, and it can escape from him? If so, how can you escape My decree?!

Malbim: It is known that a Kefir (young lion) does not go outside to tear. It sits in its den to ambush animals that pass by ? it roars "mi'Me'onaso". When it ages, it is called Arye, and it distances from its den to tear. The Nimshal is Melech Ashur. Both when he roared in Yisrael's land, and what he caught from them in his residence, when Hoshe'a ben Elah came to him and he incarcerated him, like a young lion traps what comes to his place ? in both cases, no one could save from him.