Midrash sa Levitico 24:1: Bamidbar Rabbah & Vayikra Rabbah

“Israel was dwelling in Shitim, and the people began to engage in harlotry with the daughters of Moav” (Numbers 25:1).
“Israel was dwelling in Shitim” – halakha, due to the merit of several matters, Israel was redeemed from Egypt. Our Rabbis taught: Due to the merit of four matters, Israel was redeemed from Egypt: Because they did not change their names; because they did not change their language; [because] they did not reveal their secrets, as Moses said to them: “Each woman will borrow from her neighbor silver vessels and gold vessels” (Exodus 3:22) – this was entrusted to them for twelve months and not one of them revealed it to the Egyptians, and [because] they did not behave with licentiousness, as it is written: “A locked garden is my sister, my bride” (Song of Songs 4:12) – these were the males; “a locked fountainhead, a sealed spring” (Song of Songs 4:12) – these were the maidens. Know that there was one,⁷⁷Who had a child from an Egyptian. and the verse publicized her: “The son of an Israelite woman went out, [and he was the son of an Egyptian man]” (Leviticus 24:10). All those forty years, they did not sin until they came to the Shitim. That is why it is written: “Israel was dwelling in Shitim, and the people began to engage in licentiousness” – Shitim, because they performed foolishness [shtut]. “One who commits adultery with a woman lacks a heart” (Proverbs 6:32).⁷⁸“Lacks a heart” in the sense that he is a fool. Throughout Proverbs, somebody who "lacks a heart" is a fool. I Kings 3:12 describes that Solomon was granted a "wise heart."
“The people began to engage in licentiousness” – there are springs that produce the mighty, and some [that produce] the weak, some fair and some ugly, some chaste, and some steeped in lewdness. The Shitim spring was one of harlotry, and it provided water for Sodom. You find that they said: “Where are the men who came to you tonight? Bring them out to us, [and we will be intimate with them]” (Genesis 19:5). Because that spring was cursed, the Holy One blessed be He is destined to dry it, as it is stated: “A spring will emerge from the House of the Lord and will irrigate the Shitim ravine” (Joel 4:18). From the time of Abraham, not one of them behaved with harlotry. When they arrived at the Shitim and drank its water, they behaved with harlotry.

Rabbi Yitzḥak began: “Your saying is exceedingly pure, and Your servant loves it” (Psalms 119:140) – like the goldsmith who inserts the gold into the crucible two or three times until he purifies it, so this portion was stated, repeated, and repeated a third time.²The mitzva to light the lamps in the Tabernacle or Temple was taught in Exodus (27:20–21), Leviticus (24:1–4), and Numbers (8:1–4). This is in order to clarify all the details of the mitzva and help the people remember it (see Maharzu). The matters can be inferred a fortiori: If this small portion in the Torah is stated, repeated, and repeated a third time, the rest of the portions in the Torah, all the more so.³Other passages, which are far more extensive, must have also been repeated to the people. The mitzvot were taught at Sinai, repeated at the Tent of Meeting, and repeated a third time on the plains of Moav (Maharzu).