"And We gave Moses and Aaron the Criterion," meaning: the Torah, and its criterion is that He differentiated within it its lawful and its unlawful matters.
﴿وَلَقَدْ آتَيْنَا مُوسَى وَهَارُونَ الْفُرْقَانَ﴾ يَعْنِي: التَّوْرَاةَ، وفُرْقَانُهَا أَنَّهُ فَرَّقَ فِيهَا حلالها وحرامها.