A Debt Owed Since the Gods Made the Sun Move

Aztec myth told that at Teotihuacan, before the present sun existed, the gods gathered in darkness and had to sacrifice themselves so that a newly risen sun and moon would move across the sky at all. Nanahuatzin, a humble and diseased god, cast himself into a sacrificial fire to become the sun; the assembled gods then had to sacrifice their own hearts and blood to give the new sun the strength to rise and travel. Humanity itself was formed, in a companion myth, from bones the god Quetzalcoatl retrieved from the underworld and moistened with blood drawn from his own body.

From this double origin, Aztec religious thought concluded that human existence and the sun's continued motion were both already purchased at divine cost, so every person and the cosmos itself lived on borrowed substance. Nextlahualli named the ongoing repayment this debt demanded: not a single transaction but a continuous obligation, discharged through the whole spectrum of Aztec ritual life, that recognized the gods' self sacrifice as the reason anything existed to be religious about in the first place. The Florentine Codex records priests reciting this creation account explicitly to explain why offerings continued to be necessary, tying the sun's daily journey directly to the community's ongoing ritual obligation rather than treating either as settled once and for all.