Is "I am Hashem your God" a commandment?
It is the first of the ten. Whether it is also one of the 613 is an old argument.
The Rambam says yes. Sefer HaMitzvot opens with it: the first positive mitzvah is to know that there is a First Being who brings everything else into existence. He builds the opening chapter of Yesodei HaTorah on it. On this reading אָנֹכִי is not a preamble at all, it is the obligation that every other obligation rests on.
The Behag says no. Halachot Gedolot leaves it out of the count of 613. The reasoning is that a king who announces himself has not yet issued an order. The declaration establishes who is speaking; the commands begin after it. The Ramban takes this seriously enough to defend it at length in his notes on Sefer HaMitzvot.
Notice that the argument is never about whether it is one of the ten. It is first among the ten in every Jewish reckoning. The question is narrower and sharper: can knowing something be commanded?
There is a detail in the text that lines up with all of this. The first two statements speak in the first person: "I am Hashem your God," "you shall have no other gods before Me," "for I am Hashem your God, a jealous God." From the third onward the text switches to the third person: "the name of Hashem your God," "for Hashem will not clear."
The Gemara in Makkot 24a gives the reason. Rabbi Simlai counts 613 mitzvot, and derives the number from תּוֹרָה צִוָּה לָנוּ מֹשֶׁה, whose gematria comes to 611. The missing two are named directly:
The first two came straight from God, and the nation heard them in God's own voice. The remaining eight came through Moshe. That is why the grammar turns: after the second statement, someone else is doing the speaking.
One last thing the English hides. The Torah does not call them commandments. It calls them עֲשֶׂרֶת הַדְּבָרִים (Devarim 4:13 and 10:4), the ten statements. Which is exactly why the first one can be a statement and still be first.
Shemot and Devarim do not match
The Ten Commandments appear twice in the Torah, and the wording is not identical.
Shabbos is the big one. Shemot opens with זָכוֹר, remember, and gives creation as the reason: God made the world in six days and rested. Devarim opens with שָׁמוֹר, guard, and gives the Exodus as the reason: you were a slave, and now your servants rest as you do. The Gemara (Shevuot 20b) says both words were spoken in a single utterance. That line is not an academic footnote, it is sung at every Friday night table in Lecha Dodi: שָׁמוֹר וְזָכוֹר בְּדִבּוּר אֶחָד.
The ninth changes one word. Shemot forbids an עֵד שָׁקֶר, a lying witness. Devarim forbids an עֵד שָׁוְא, an empty one.
The tenth reorders and re-verbs. Shemot: the house, then the wife, with תַחְמֹד both times. Devarim: the wife, then the house and the field, with the second verb becoming תִתְאַוֶּה.
And Devarim keeps adding a clause: כַּאֲשֶׁר צִוְּךָ ה' אֱלֹהֶיךָ, "as Hashem your God commanded you," on both Shabbos and honoring parents, plus a second promise on parents, that it will go well with you. Devarim is Moshe retelling Sinai forty years later to people who were not standing there.
The Compare view above highlights every word that differs, verse by verse, in whichever cantillation you have selected.
Two sets of cantillation marks
The same words carry two different ta'amim, and they cut the passage into different verses.
Under ta'am elyon the second statement runs from "no other gods" all the way to "those who love Me and keep My commandments" as a single verse, and the fourth runs the whole of Shabbos as a single verse, while murder, adultery, theft and false witness each become a verse of two or three words. Under ta'am tachton those four share one verse and the long ones are broken up normally.
The widespread practice is ta'am elyon for the public Torah reading of the Ten Commandments, on Shavuot and on Parshat Yitro and Parshat Vaetchanan, and ta'am tachton for private review such as shnayim mikra. Communities vary, so this is a question for your own rav rather than a single rule.
If the marks themselves are unfamiliar, our free trope and ta'amei hamikra trainer teaches each one with interactive cards.
Why they are not in the daily davening
They used to be. The Mishnah records that the Ten Commandments were said every day in the Beis Hamikdash, alongside Shema. The Gemara in Berachot 12a reports that communities outside the Mikdash wanted to say them daily too, and that the practice was stopped מִפְּנֵי תַּרְעוֹמֶת הַמִּינִין, because of the claims of the sectarians: if these ten are the daily text, someone will conclude that only these ten were given at Sinai.
The same concern shows up later around standing for the reading. The widespread custom is to stand when the Aseret HaDibrot are read from the Torah. The Rambam, asked about a community that did so, discouraged it for exactly the reason above, that singling the passage out implies the rest is worth less. Most communities stand anyway, and there are strong defenses of the custom. It is a live disagreement, not a settled error.
What survived is quieter: many siddurim print the Ten Commandments after Shacharit as a private reading rather than part of the order of prayer. The distinction is deliberate.
Questions people actually ask
Is "thou shalt not kill" a correct translation?
No. The Hebrew is לֹא תִרְצַח, from ratzach, which means murder. The general verb for killing is harag, and it is not the word used here. The same Torah commands killing in war and through the courts, so "do not kill" makes the text contradict itself. The long-standing English rendering is the source of most of the confusion.
Why is honoring parents on the God side of the tablets?
Five and five is the classic division, and honoring parents is the fifth, which puts it on the first tablet with the statements about God rather than with the ones about other people. The reason usually given is that parents are partners with God in bringing a person into the world, so the honor owed them belongs to the same category. It is also the only one of the ten that comes with a reward attached.
Does the eighth commandment mean stealing objects?
The Gemara in Sanhedrin 86a reads לֹא תִגְנֹב here as kidnapping, stealing a person, because of the company it keeps: it sits between murder and false testimony, which are capital matters. Stealing property is certainly forbidden, but the Torah says so elsewhere, in Vayikra 19:11.
How can a commandment govern what you want?
The tenth is the odd one out: nine of the ten govern what you do, and this one governs what you want. Ibn Ezra's answer is the well known one, that desire is trainable. A person does not covet what is genuinely out of their category, the way a villager does not lie awake wanting to marry the princess. Build the right sense of what is yours and the wanting does not start.
Were they really carved on two stone tablets?
Yes, and the Torah says the writing went through the stone from both sides (Shemot 32:15). Whether the two tablets held five and five, or the whole text twice as a treaty copy for each party, is an old discussion. The five and five reading is the one reflected in the layout on this page.
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