The Hebrew says “devarim” (“words”) - not “mitzvot” (“commandments”).
I’m no longer the note-taker for the Hirshleifer-Rosett  Faculty Tanakh Study Group, so I haven’t been reporting on its activities in this space, but it continues to flourish; we’re now reading Exodus, and today we hit Chapter 20, the Ten Commandments.
Or, as it turns out, not.
It’s news to me, as no doubt to most of you, but that phrase does not occur in the Biblical text. In Exodus 32:28, when the original pair of tablets is replaced, the new tablets are referred to as containing “the words (דִּבְרֵי, divarai) of the covenant, the ten words (עֲשֶׂרֶת ×”Ö·×“Ö¼Ö°×‘Ö¸×¨Ö´×™× , asheret ha-devarim).” (For reasons utterly obscure to me, the later tradition uses debrot, the feminine plural, rather than the masculine plural devarim.)
There’s no ambiguity here. “Commandment”  (מִצְוָה, mitzvah) is a key-term in the text, and in Jewish tradition. Its root is the word for “command,” or perhaps it would be better rendered as “instruction” or “guidance.”  A mitzvah is that which one is commanded or instructed or guided to do; the Talmudic rabbis counted 613 of them in the Torah.
Devar, by contrast, means “word” or “statement” or “speech”: thus the Greek “Decalogue.”  In particular, what the Jewish tradition has always counted as the first of the asheret devarim - “I am HaShem your God, who has brought you out of the land of Egypt, out of the house of bondage” - is not a command, but a statement of fact. It serves as the first of ten clauses making explicit the covenant to which the Children of Israel had already assented (Ex. 19:8).
I’m not sure when or how the mistranslation happened. But once again we see the great wisdom of the founders of Harvard College (as a Congregationalist seminary) in requiring entering students to know Hebrew.
Update Commenter Raghav Krishnapriyan corrects my Hebrew. (Only in America!):
