The LORD spoke to Moses, saying: Tell the Israelite people to bring Me gifts; you shall accept gifts for Me from every person whose heart so moves them.
God commanded that the procedure should not be like the imposition of every person's contribution for the public charity fund which was treated as a tax. Contributions were to be accepted only from volunteers.
Oh Lord prepare me, to be a sanctuary, pure and holy, tried and true
And with thanksgiving, I'll be a living, sanctuary, for you
קדשׁ to be holy, be sacred.
— Qal - קָדַשׁ 1 was set apart, was consecrated; 2 was forbidden.
— Niph. - נִקֽדַּשׁ 1 was hallowed, was sanctified, 2 was consecrated, was dedicated.
— Pi. - קִדֵּשׁ 1 he hallowed, sanctified; 2 he dedicated; consecrated; 3 he declared holy; 4 he cleansed, purified; 5 he devoted, assigned; PBH 6 he sanctified the Sabbath or the festivals; PBH 7 he pronounced the benediction of Kiddush; PBH 8 he made something prohibited; PBH 9 he betrothed, wedded.
— Hith. - הִתְקַדֵּשׁ 1 he kept himself separated, purified himself; 2 he became sanctified; 3 he prepared himself; PBH 4 it was forbidden (as food).
— Hiph. - הִקְדִּישׁ 1 he set apart as holy, devoted as holy; 2 he regarded as holy; 3 he designated, appointed; NH 4 he dedicated.
וְעָשׂוּ לִי מִקְדָּשׁ וְשָׁכַנְתִּי בְּתוֹכָם (שמות כה, כח). אֵימָתַי נֶאֶמְרָה לְמֹשֶׁה הַפָּרָשָׁה הַזּוֹ שֶׁל מִשְׁכָּן, בְּיוֹם הַכִּפּוּרִים עַצְמוֹ, אַף עַל פִּי שֶׁפָּרָשַׁת הַמִּשְׁכָּן קוֹדֶמֶת לְמַעֲשֵׂה הָעֵגֶל.
אָמַר רַבִּי יְהוּדָה בְּרַבִּי שַׁלּוּם: אֵין מֻקְדָּם וּמְאֻחָר בַּתּוֹרָה, שֶׁנֶּאֱמַר: נָעוּ מַעְגְּלֹתֶיהָ לֹא תֵדָע (משלי ה, ו), מְטֻלְטָלוֹת הֵן שְׁבִילֶיהָ שֶׁל תּוֹרָה וּפָרָשִׁיּוֹתֶיהָ. הֱוֵי, בְּיוֹם הַכִּפּוּרִים נֶאֱמַר לְמֹשֶׁה וְעָשׂוּ לִי מִקְדָּשׁ.
And let them make Me a sanctuary, that I may dwell among them (Exod. 25:8). On which day did God relate to Moses the portion relating to the Temple? It was on the Day of Atonement. That was so despite the fact that the Torah portion describing the Sanctuary precedes the incident of the golden calf.
R. Judah the son of R. Shalum said: There is actually no such thing as preceding or following in the Torah, as is said: Lest she should walk the even path of life, her ways wander, but she knoweth it not (Prov. 5:6). This verse refers to the arrangement of the Torah and its sections. Hence, it was on the Day of Atonement that God told Moses: Make Me a Sanctuary.

“Perhaps this is telling us that until two people interact, they don’t share the same reality – because it is communication itself that creates it.”
(ה) ועשו לי מקדש ושכנתי בתוכם. ודקדקו המפורשים אמאי לא כתיב ושכנתי בתוכו. י"ל דקאי על עיקר השראת השכינה שהי' על פנימיות נדבת לבם של כל או"א בדיבורו שהיו מקדישים נדבותם לצרכי המשכן היו ממשיכים אז בדיבורם הקדושה והי' השכינה שורה על פנימיות הלב של כל אחד ואחד בשעת דיבורו והקדשו. ומפני זה כתיב ושכנתי בתוכם ר"ל בתוך הפנימיות לבבם של המתנדבים. ומזה יש ללמוד כמה גדול כח הדיבור של בנ"י...
Many commentators discuss the issue with why it talks about within them as opposed to within it. For me, this all rests upon the essence of how God's presence dwells among us. To me, it's all based on the inner workings of a person's offering through their speech. For they would consecrate, even through their words to the sanctity of the Tabernacle. The presence of God would then dwell based on that intention.
For this reason, [the Torah] writes I will dwell within them. That is to say, within the essence of the hearts of the givers. From this we learn the great strength of speech...
Translated by Rabbi Adir Yolkut