The Koran is clearest on the prohibition against incest

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“But if any man thinks that he is behaving himself unseemly toward his virgin daughter, if she be past the flower of her age, and if need so requires, let him do what he will; he is not sinning; let them marry” (1 Cor. 7:36).

WITH 4:23 OF THE KORAN:

"Prohibited to you [for marriage] are your mothers, your daughters, your sisters, your father's sisters, your mother's sisters, your brother's daughters, your sister's daughters, your [milk] mothers who nursed you, your sisters through nursing, your wives' mothers, and your step-daughters under your guardianship [born] of your wives unto whom you have gone in. But if you have not gone in unto them, there is no sin upon you. And [also prohibited are] the wives of your sons who are from your [own] loins, and that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is ever Forgiving and Merciful."

As for the Old Testament, we know from Genesis 19:30-38 that Lot had sex with his two daughters and had offspring.

https://www.biblegateway.com/passage/?search=Genesis+19%3A30-38&version=NIV

Lot and His Daughters

30 Lot and his two daughters left Zoar and settled in the mountains, for he was afraid to stay in Zoar. He and his two daughters lived in a cave. 31 One day the older daughter said to the younger, “Our father is old, and there is no man around here to give us children—as is the custom all over the earth. 32 Let’s get our father to drink wine and then sleep with him and preserve our family line through our father.”

33 That night they got their father to drink wine, and the older daughter went in and slept with him. He was not aware of it when she lay down or when she got up.

34 The next day the older daughter said to the younger, “Last night I slept with my father. Let’s get him to drink wine again tonight, and you go in and sleep with him so we can preserve our family line through our father.” 35 So they got their father to drink wine that night also, and the younger daughter went in and slept with him. Again he was not aware of it when she lay down or when she got up.

36 So both of Lot’s daughters became pregnant by their father. 37 The older daughter had a son, and she named him Moab[a]; he is the father of the Moabites of today. 38 The younger daughter also had a son, and she named him Ben-Ammi[b]; he is the father of the Ammonites[c] of today.