Midrash su Levitico 18:19

(Fol. 13a) At the academy of Elijah it was taught: "Once it happened that a scholar who read (the Scripture) to a great extent and studied a great part (of the Talmud) and devoted much of his time in attendance upon the scholars, died very young, and his wife took his Tephilin and went around with them to every place of worship and study saying to the audience: 'Behold it is written in the Torah (Deu. 30, 20.) For He is thy life, and the length of thy days. My husband studied and read so much and (Fol. 13b) gave so much of his time to attendance upon the scholars; why did he die so young?' And there was none who could give her answer. I happened once to stop at her house and she told me everything that had happened to her. I said to her: 'My daughter, how did he conduct himself during the days in which you were a Niddah?' She answered: 'God forbid! He refrained even from touching my little finger.' 'And during the days when you were a Lebuna, how was his conduct towards thee?' I asked her again. Whereupon she answered: 'He ate with me, drank with me, and did not refrain from touching me.' I then said to her: 'Praised be the Holy One, who spared him not for the sake of scholarship, for the Torah says (Lev. 18, 19.) And a woman in the separation of her uncleanliness shalt thou not approach.' " When K. Dimi came he said: "They were together in one bed [while in her Lebuna"]." In Palestine it was said, in the name of R. Isaac b. Joseph, that she wore breech cloth [while with him in one bed].

Set about with lilies. Does a man ever fence in his fields with lilies? Does he not normally fence in his fields with thorns and thistles, with pits and thornbushes? What then is the meaning of Set about with lilies? This refers to numerous commandments that are as sensitive as lilies. For example, a man is extremely anxious to enter his bridal chamber, for no day is dearer to him than that day. It is the day on which he rejoices with his bride. What does he do? He spends a considerable amount of money to set up the bridal chamber and he comes to have intercourse with her. But if she says to him: “I have seen something like a red lily (i.e., the blood of menstruation), he draws away from her. He turns his face to one side and she to the other. What compelled him to turn from her? Was it a snake biting him, a scorpion stinging him, or a thorn between them? No, only the words of the Torah, since it is said: And thou shalt not approach a woman to uncover her nakedness, as long as she is impure by her uncleanness (Lev. 18:19). Hence it is written: Set about like lilies.

“Your belly is a pile of wheat,” this is the book of Leviticus. Just as the belly, the heart is on this side and the legs are on the other side and it is in the middle, so is the book of Leviticus, there are two on this side and two on that side and it is in the middle.²⁶Leviticus is the third of the five books of the Pentateuch. “A pile of wheat [ḥitim],” a pile of sins [ḥata’im];²⁷Leviticus details the laws of sin-offerings (Matnot Kehuna). “hedged with lilies,” these are matters of Torah, which are as soft as lilies. How many mitzvot and details are in the book of Leviticus, how many a fortiori inferences, instances of piggul²⁸An offering is disqualified if, in the course of the four sacrificial rites, one has the intent to sprinkle the blood or eat the flesh of the offering beyond its appointed time. Such an offering is called piggul. and instances of notar²⁹This is flesh that is left over after the appointed time for its consumption. there are in the book of Leviticus.
Rabbi Levi said: It is the way of the world that a man might marry a woman at the age of thirty or forty years. After he outlays all his expenditures, he comes to consummate his marriage with her; if she says to him: I saw [a spot] like a red lily,³⁰Menstrual blood. he separates from her immediately. Who caused him not to approach her? What iron wall is between them? What iron pillar is between them? What snake bit him? What scorpion stung him so that he would not approach her? [There is but] the words of the Torah, which are as soft as lilies, in which it is stated: “You shall not approach a woman in her state of menstrual impurity” (Leviticus 18:19).
Likewise, one before whom they brought a tray of pieces [of meat]; if they say to him: [A piece of] forbidden fat fell there, he withdraws his hand and does not taste it. Who caused him to refrain from tasting? What snake bit him so that he would not taste it? What scorpion stung him so that he would not approach and taste it? The words of the Torah, which are as soft as lilies, in which it is written: “You shall not consume any fat or any blood” (Leviticus 3:17).