1)
Why did he call himself "Ba'ar"?
1.
Rashi: I did not know this matter; I was like an animal.
2.
Radak: It is a man without Da'as, just like Hashem created an animal. I was like an animal in serving You; I did not know whether or not there is reward.
2)
Why did he say "Hayisi Imach"?
1.
Malbim: Regarding what I did not know, I was like an animal with You; its life is physical. Man's body is not different than an animal. Success and afflictions in this world, man does not get them, only the animal part of him. It is only a residence for man himself, or his clothing.
