Jephthah's daughter, you guys. Judges 11. One hundred percent canonical human sacrifice to the Hebrew God. In fairness, God's reaction to having had a virgin sacrificed to Him is not recorded, and at least one scholar has latched on to this as evidence that He didn't like it. But God's so stridently opposed to human sacrifice elsewhere that you'd think He'd kick up a fuss about it, wouldn't you? Some scholars say He doesn't because Jephthah doesn't actually kill his daughter, but rather keeps her locked up forever, like a kind of Jewish proto-nun. That doesn't make a lot of sense to me either, given how obsessed the entire Bible is with female fecundity; to the Jewish mind, lifelong virginity is a terrible waste. (On more than one occasion my father has expressed his bafflement at the Catholic insistence on celibacy for its priests: "Let's take the smartest, best-educated men in the community," he'll say, "and make sure they don't have children.") But then, maybe that's the point: if a woman's fertility is the measure of her value, preventing her from having children is tantamount to killing her. Only without that pesky wrath of God. But why would she ask her father for two months to "bewail my virginity" if she was going to have the rest of her life to bewail it? I always took that to mean that she wanted some time to mourn the fact that she'd never be a wife or a mother because she'd be, you know, dead.
Possibly the single most poignant thing about the story of Jephthah's daughter is that she doesn't have a name. It's as if the only thing of importance about her is her relationship to a man. Women in the Bible are often nameless: Moses's mother, Pharaoh's daughter, the Samaritan woman, Lot's wife. It's more poignant here, though, because there's such an obvious parallel to the story of the sacrifice of Isaac. It's not just that God saved Isaac and did not save Jephthah's daughter; it's also that we know Isaac's name, and by we I don't just mean "weirdo Bible nerds." Isaac's name and his story are common knowledge, and he is venerated as a patriarch. I've known several Isaacs personally. But Jephthah's daughter is a footnote.
Much of the Hebrew Bible is retold in a Jewish writing from about two thousand years ago called Pseudo-Philo, or if you want to get fancy Liber Antiquitatum Biblicarum (Book of Biblical Antiquities). Here Jephthah's daughter is called Seila, so at least someone had the decency to name her.