Sforno on Leviticus 19:2/ספורנו על ויקרא י״ט:ב׳

1דבר אל כל עדת...קדושים תהיו; after the presence of G’d had manifested itself among the Jewish people, sanctifying them for eternal life, as had been the meaning of the verse in Exodus 19,6 “you shall become for Me a nation of priests a holy nation,” and taking into consideration G’d’s statement in Leviticus 11,45 “I have led you out of the land of Egypt in order to be your G’d and your becoming holy,” G’d had in the meantime separated the Jewish people from impurity through the legislation concerning forbidden foods, skin eczemas, ritual impurity contracted through cohabitation with menstruant women, or women afflicted with excretions from their vaginas at times other than when they were experiencing menstruation. G’d had also elaborated on other ritual contaminations contracted through sinful contact. The objective of all these parts of Torah legislation was to establish a nation that could be described as “holy,” not least of it the legislation concerning incest. At this point, i.e. after achieving this “holiness,” i.e. emulating the Creator’s holiness in the maximum manner possible for creatures, the Torah spells out this objective by saying כי קדוש אני, “For I the Lord am holy;” the message is that the original intention in creating man in the image of G’d (Genesis 1,26) had already had as its declared goal for this “image” to become something constant. The Torah now proceeds to list laws which appeared on the first of the Two Tablets, whose objective it is to ensure enduring life for the Jewish people as we explained on Exodus 20,11.