It’s in the Bible. You’re probably thinking of Jesus and Isaac. Isaac almost got sacrificed because god wanted to test Abraham’s obedience, even though being an omniscient deity, you’d think he’d already know the outcome and spare the kid a traumatic experience. I take that back. The god of the Bible is a jerk, so he wouldn’t care about the kid emotional well being. Jesus’s sacrifice is a can of worms in itself. It’s not exactly a sacrifice since he got resurrected, according to the story. People like me are baffled by the contortions Christians go through to make it necessary. The whole trinity thing is just surreal with one entity sacrificing itself to itself. It gets nastier in some interpretations where Jesus replaces regular death with Hell and expects us to play Pascal’s Wager on his particular horse out of the infinity of metaphysical beliefs. This is familiar ground for a lot of us.