Rashi: Just like you err about this, you err about many laws.

Malbim: The nation is like an answer to the question. If they approach and touch Kedushah, Kedushah does not cling to them. If they approach and touch Tum'ah, Tum'ah clings to them, and they become like it.

Radak #1: The matter is repeated [in different words].

Radak #2, Malbim: "Ha'Am" refers to the Kohanim. "Ha'Goy" is Yisrael. You are all guilty about [not] building the Bayis. The Kohanim should have warned the nation to build.

Malbim: Just like in the Mashal, if Chulin touches Kodesh, it becomes Kadosh only if it absorbed in it, so Kedushah cling to a person only if he swallows it and it enters him, i.e. he grabs it in his heart and inner Nefesh, but not if he merely touches it externally. The external body has no connection to Kedushah; it is a spiritual matter. Tum'ah pertains to the body; it clings to it merely via touching. The deeds of their hands are external; they are not of their heart and Nefesh, therefore Tum'ah clings to them.

Rashi: If they will not puts to their hearts to learn [they will err, and offer Tamei Korbanos].

Radak (12-13): This is not difficult for the opinion that the Kohanim answered correctly both times. Even though they know the law of Tum'ah and Taharah, what they offer in front of Me, it is as if it is Tamei, since they offer on a Mizbe'ach without a Bayis; they are lazy about building the Bayis. They are not concerned for My honor! The verses prove that they did not err, just he rebuked them about the Bayis.

Malbim: Since they do not offer in front of Hashem with Kedushah - a Korban of the Nefesh with the proper intent, rather, they offer Sham... "Sham" refers to a far, physical place. They offer a physical, animalistic Korban on rocks. The Tum'ah of their bodies and land clings to it. This shows that they did not yet become Kadosh to cling to Kedushah and build the Mikdash and spiritual Mizbe'ach in the heart and Nefesh - then their Nefesh ascends to Hashem!