Rashi: The extent of your rebellion was deep. I said that anyone who does not ascend for the Regel transgresses an Aseh. They decreed that anyone who ascends for the Regel will be killed! They went deeper than Me! V'Shachatah is like "Zahav Shachut" (Melachim I, 10:16) ? drawn and spun.

Rashi citing Targum Yonasan: V'Shachatah is an expression of Shechitah of Korbanos to idolatry.

Radak: V'Shachatah is Makor (infinitive), for there is a Patach under the Shin. Its grammatical form is like Le'ahavah. Setim are idolaters, who stray from Hashem's ways and His Avodah, like a woman who is Sotah ¹ under her husband. They rebelled deeply, to slaughter Korbanos to idolatry.

Malbim: People were careful not to pass on the mountains, and veered from the path to descend to the valley, where there were no guards. If they were caught on their way, [the guards] would slaughter them. The Shechitah was of Beis ha'Melech, for they appointed people to do so.

Rashi: It is affliction; I will prepare afflictions for all of them.

Radak: It is chastising. Do not say that they sin because no one straightens them and rebukes them. I chastise them every day, and they do not heed Me! It should say va'Ani Ish Musar; 'Ish' is omitted, just like "va'Ani Tefilah" (Tehilim 109:4) ? I am an Ish Tefilah.

Malbim: I, the Navi, was appointed to rebuke with words of Musar and return them in Teshuvah ? but I knew that my Musar will not help.