The rationale for Aztec human sacrifice was, first and foremost, a matter of survival. ... The keep the sun moving across the sky and preserve their very lives, the Aztecs had to feed Huitzilopochtli with human hearts and blood
Politically human sacrifice was important in Aztec culture as a way to represent a social hierarchy between their own culture and the enemies surrounding their city. Additionally, it was a way to structure the society of the Aztec culture itself