Hashem commanded "v'Harasta Es Mizbach..." (verse 25). Why does it say "Nutatz"?
Malbim: Harisah is dissembling something built. Netitzah is breaking every rock into pieces. Really, he only dissembled it; he built a new Mizbe'ach from the intact rocks, but they did not know this. (They assumed that he was Notetz.)
Why does it say "v'Es ha'Par"?
Malbim: This includes the Asheirah with the ox.
Why does it say "ha'Mizbe'ach ha'Banuy"?
Malbim: Surely the people of the city destroyed the Mizbe'ach built on the bottom one, but they could not destroy the bottom one; it was called Ma'oz. This is why Hashem called it Shalom!
Why is there no mention of the first ox?
Refer to 6:25:3:1.