Exode 15:25

And he prayed before the Lord, and the Lord showed him the bitter tree of Ardiphne; and he wrote upon it the great and glorious Name, and cast it into the midst of the waters, and the waters were rendered sweet. And there did the Word of the Lord appoint to him the ordinance of the Sabbath, and the statute of honouring father and mother, the judgments concerning wounds and bruises., and the punishments wherewith offenders are punished; and there he tried (them) with the tenth trial,

THERE HE MADE FOR THEM A STATUTE AND AN ORDINANCE, AND THERE HE TRIED THEM. “At Marah He gave them some of the sections of the Torah so that they might engage in the study thereof, [such as]: the Sabbath, the Red Heifer, (a statute), the type of a commandment the reason for which we do not know. The laws of justice are the typical examples of mishpat (ordinance), which is a precept dictated by reason. Accordingly Rashi interpreted the verse before us — a statute etc. — as referring to these three subjects. and the laws of justice. And there He tried them, that is, the people.”. It should have said, “There He made for them a statute and an ordinance and tried them,” in which case it would have meant that He tried them with the statute and ordinance, i.e., to see if they would observe them. But since it says, and there He tried them, it must refer to something additional, namely, the preceding event when the people murmured against Moses instead of approaching him to pray that the bitterness of the waters be removed. It is to this event, according to Rashi, that the expression refers: “And there He tried them, that is, the people” (Sifthei Chachamim). Ramban, however, will explain that “the trial” was of another nature, as will be explained in the text. Thus the language of Rashi, and it is the opinion of our Rabbis.
But I wonder! Why does Scripture not explain these statutes and ordinances here, saying, “And the Eternal spoke to Moses: ‘Command the children of Israel,’” as it says in the chapters mentioned above, Speak ye unto all the congregation of Israel? Indeed, it does so with regard to all commandments given in the Tent of Meeting, on the plains of Moab, and the Passover in the wilderness!, 9:1-5. Now Rashi’s expression, “He gave them… sections of the Torah so that they might engage in the study thereof,” indicates that Moses did inform them of these statutes and that he taught these statutes to them, [saying], “In the future, the Holy One, blessed be He, will command you so,” in the same way as Abraham our father learned the Torah. The purpose of it was to make them familiar with the commandments and to know if they would accept them with joyfulness and with gladness of heart. This was “the trial” of which Scripture says, and there He tried them, and he [Moses] informed them that G-d would further command them the precepts of the Torah. This is the intent of the verse, “If …