Positive commandment · Mitzvat Aseh #20 of 613
To build [G-d's] chosen house, [the Temple,]
לִבְנוֹת בֵּית הַבְּחִירָה
The verse · Shemot 25:8
וְעָשׂוּ לִי מִקְדָּשׁ וְשָׁכַנְתִּי בְּתוֹכָם
“And let them make me a sanctuary; that I may dwell among them.”
The Rambam’s words
To build [G-d's] chosen house, [the Temple,] as [Exodus 25:8] states: "And you shall make a sanctuary for Me."
לִבְנוֹת בֵּית הַבְּחִירָה, שֶׁנֶּאֱמָר: "וְעָשׂוּ לִי מִקְדָּשׁ" (שמות כה, ח).
Why · Sefer HaChinuch #95
Building the Choice House
“From the roots of the commandment are what you will see at the end of my words. However, I am afraid of drawing close to the Dwelling of G-d, as I know that “anyone who comes close, who comes close” that has not sufficiently sanctified himself “will not see the House and live.””
Who & when
“And this commandment is practiced at the time that most of Israel is upon their Land.”
Where in the Mishneh Torah
Hilchot The Chosen Temple הלכות בית הבחירה