Why does it say "Eich Tomri"?
Radak: Your sin is so exposed that if you wanted to deny it, you cannot.
Radak, based on Targum Yonasan: Refer to 2:23:3:1.
Malbim: How can you deny (a) that you became Tamei (served idolatry), and (b) that you went after the Ba'alim to become Tamei?!
What is the "Gai"?
Rashi: It is opposite Ba'al Pe'or - and you still go in that way!
Radak: Even though they sinned on the hills ("Al Kol Giv'ah" - verse 20), your path is trodden in the valley to ascend to the hill. It mentions the valley, for the path is recognized better in the valley than in the hill. The path was only to go the hill to offer Olos! The path was trodden so much that it was evident to all. The only path in the valley is to the nearest hill.
What is the meaning of "see your way"?
Radak citing Targum Yonasan: Lift your eyes, and see that your way [is like earlier]. You sat in the valley opposite Ba'al Pe'or [and sinned with Ba'al Pe'or. Also now, you follow the Ba'alim. You cannot deny this!]
Malbim: The mark of your footsteps is evident. How can you say 'I did not go'?!
Why did He say "know what you did"?
Radak: Know your Avodah of Ba'al on the hill.
Sha'arei Teshuvah 1:36: One must investigate and know the great punishment for each of his Aveiros, and cry bitterly that he angered Hashem. This knowledge will increase his huikity and fear of his sins, for severe sins, Teshuvah suspends their Kaparah, and afflictions complete it.
Malbim: You know that you served idolatry. How can you say 'I did not become Tamei'?!
What is "Bichrah Kalah"?
Rashi: It is a young female camel that loves to wander. The Targum of "Bi'Chrei Midyan" (Yeshayah 60:6) is Hognei Midyan, i.e. young camels. 'Many old camels carry the skins of young camels' (Sanhedrin 52a; the latter died because they were not trained to bear a burden). Radak - a young female camel runs more than a male.
What is the meaning of "Mesareches"?
Rashi: It persists in the way of its youth. This is like Misrach Sarich (Chulin 51a). We can say that this is related to "Seruch Na'al" (Bereishis 14:23) - it ties the ways of its youth in its heart. Radak - the lace is tied many times around the shoe.
Radak: It varies the path [in which it runs] - once here, and once here. So you - once you serve this idolatry, and once this idolatry.
Radak citing Targum Yonasan: It ruins its ways.
Malbim: It digs its feet into the path; it is evident where it went. So your footsteps are evident!
