(Originally delivered at Temple Israel, Friday night, 1/21/2011.)
Because of the centrality of the Decalogue (often known as the "Ten Commandments," even though you might be able to count as many as 13 separate mitzvot within that passage), we often overlook the fact that as soon as they have been issued, God simply keeps talking. The mitzvah count keeps going up.
For example, just a few verses later, God tells Moses the following (Ex. 20:21):
;מִזְבַּח אֲדָמָה, תַּעֲשֶׂה-לִּי, וְזָבַחְתָּ עָלָיו אֶת-עֹלֹתֶיךָ וְאֶת-שְׁלָמֶיךָ, אֶת-צֹאנְךָ וְאֶת-בְּקָרֶךָ
.בְּכָל-הַמָּקוֹם אֲשֶׁר אַזְכִּיר אֶת-שְׁמִי, אָבוֹא אֵלֶיךָ וּבֵרַכְתִּיךָ
"Make for Me an altar of earth and sacrifice on it your burnt offerings and your sacrifices of well-being, your sheep and your oxen;
in every place where I cause My name to be mentioned I will come to you and bless you."
Now, in a later time the officially-sanctioned place of sacrifice is the Temple in Jerusalem. But the Israelites are still standing at Mt. Sinai, at least 40 years away from arriving in Israel, and more than 200 years from the establishment of the Temple. So this is where the latter part of the verse is important: everywhere that we mention God's name is a place of holiness.
And this is especially important today, 2000 years after the destruction of the Second Temple in Jerusalem. We make the holy places, and we make the holy moments, by offering the words of prayer that we do right now, in this place and in every other place where we invoke God's name.
This is the place that God was talking about. Right here.