"There He set for them a statute and an ordinance" (Exodus 15:25). There were given to Israel eleven commandments: the seven that the sons of Noah were commanded, and Abraham concerning circumcision, and Jacob concerning the sinew of the thigh, and they added for Israel the Sabbath and the honoring of father and mother. It is taught: Israel were commanded ten commandments at Marah, the seven that the sons of Heth had accepted upon themselves, and they added to them civil laws, as it is written, "There He set for them a statute and an ordinance"; and the Sabbath and honoring father and mother, as it is written, "as the LORD your God commanded you" (Deuteronomy 5:12). Rav Yehuda said in the name of Rav: "as He commanded you" refers to Marah. (It is written in remez 52.)
The Eleven Commandments Israel Received at Marah
Yalkut Shimoni on Torah 257:1
שָׁם שָׂם לוֹ חֹק וּמִשְׁפָּט, שָׁם נִיתַּן לְיִשְׂרָאֵל אַחַת עֶשְׂרֵה מִצְוֹת, שֶׁבַע שֶׁנִּצְטַוּוּ בְּנֵי נֹחַ, וְאַבְרָהָם עַל הַמִּילָה וְיַעֲקֹב עַל גִּיד הַנָּשֶׁה הוֹסִיפוּ לְיִשְׂרָאֵל שַׁבָּת וְכִבּוּד אָב וָאֵם. תַּנְיָא, עֶשֶׂר מִצְוֹת נִצְטַוּוּ יִשְׂרָאֵל בְּמָרָה שֶׁבַע שֶׁקִּבְּלוּ עֲלֵיהֶן בְּנֵי חֵת, וְהוֹסִיפוֹ עֲלֵיהֶן דִּינִין, דִּכְתִיב שָׁם שָׂם לוֹ חֹק וּמִשְׁפָּט, שַׁבָּת וְכִבּוּד אָב וָאֵם, דִּכְתִיב (דברים ה, יב) "כַּאֲשֶׁר צִוְּךָ ה' אֱלֹהֶיךָ", אָמַר רַב יְהוּדָה אָמַר רַב, כַּאֲשֶׁר צִוְּךָ בְּמָרָה. (כָּתוּב בְּרֶמֶז נ"ב).