Who is "Arye"?
Rashi: It is Chabakuk; his name has the same Gematriya (216) as Arye. Yeshayah prophesized that later Chabakuk will pray for this, and say so.
Radak: The lookout said 'Arye Al ha'Mitzpeh'; he compared Paras and Madai to a lion that stands on a post and looks around where to tear [prey].
Radak citing Targum Yonasan: [The Navi said, the sound of camps coming strongly like] a lion
What is the meaning of "Al Mitzpeh Hashem"?
Rashi: Hashem, I stand on lookout constantly during the day, for You to inform me about this.
Why did he say "Anochi Omed Tamid"?
Radak: I stand day and night on my post, looking for when Paras and Madai's army will come to destroy Bavel, for they did evil to Yisrael.
Malbim: The lookout says, I was on my watch many days, looking for the fulfillment of Hashem's word, i.e. the fall of Bavel.
