Which Bnei Yisrael should he tell about the Bayis?
Radak: Bnei ha'Golah.
Why does it say "Haged Es Beis Yisrael"? It should say "Haged El Beis Yisrael"!
Malbim: Tell them that Beis Yisrael are the Bayis. It depends on them. All matters of the design of the Bayis show the conduct of the nation according to the Torah and its laws.
How will telling them about the Mikdash make them ashamed of their sins?
Rashi: He will show them His Chesed, that He does not despise them due to their sins.
Radak: Their sins destroyed this Bayis (Rishon). Tell them about the future Bayis, which will never be destroyed, so they will not sin ? "Yerachaku Es Zenusam? v'Shachanti v'Socham l'Olam (9).
What is the meaning of "u'Madedu Es Tachnis"?
Rashi: They will measure via you ? you will teach them the content and measure of the building.
Radak: The design of the Bayis that you will show to them, they will measure and prepare it for a Siman, that so they will do in the future, when the redeemer comes and the dead are revived. They will prepare it for a sign, that those who see this form will live in the Binyan ha'Bayis in the future. This is a proof of Techiyas ha'Mesim!
Malbim: The form of the Bayis and its details have spiritual hints to Hashem's conduct of wondrous Hashgachah that does not depend on natural orders of the world. It depends only on conduct of Beis ha'Nefesh to build and finished it like the great Bayis, and to do the Avodah arranged in Beis ha'Nefesh, i.e. guarding Torah and Mitzvos like the Avodah arranged in Bayis ha'Gadol. Nefesh ha'Chayim will go up to Hashem. Binyan ha'Bayis depends on Binyan of Beis Nafsham, according to the form of the Bayis, and according to the Midos of the Torah and its form. Direct Midos of the Nefesh according to Midos of the Bayis.
