Both professor Wartrall and the text attest to the highly stratified nature of Aztec culture. A divine king ruled over the empire and under him were nobles called pillitin. The vast majority of the Aztecs were arranged into clans, called capulli, that consisted of several lineages represented by a leader, or calpule, whom directly communicated with the imperial government on their behalf. The capullis and their members were also ranked from those that attained prestige through exceptional service to landless peasants and slaves. As has been a common trend in ancient societies, religion was used to legitimize authority and explain natural phenomenon.
This framework of power is apparent in the Aztec Creation myth(s). According to legend, due to conflict among themselves, it took the gods five attempts to create the world. Whether destruction was caused by wind, flood, or gigantic jaguar, a creator god had to sacrifice himself to become the Sun. The minor deity, Nanauatl, did so, however he remained stationary in the sky. The other gods realized that they needed to sacrifice themselves to keep the sun moving and darkness at bay. The Serpent god, Quetzalcoatl, then, retrieved human bones of previous worlds from the underworld, however, he tripped and broke the bones into different sizes. After spilling his own blood over these bones, humans of different sizes were created and expected to blood-let or perform human sacrifice. These practices would provide nourishment and support to the Sun deities Huitzilopochtli and Tonatiuh, name given to Nanauatl, to keep the Sun in motion and battle against darkness and destruction.
There are two aspects of this myth that potentially utilize religion to legitimate social structure and the outcomes associated with it. One is how Quetzalcoatl’s actions resulted in people varying in size. There is documented and archaeological proof that elites had a better diet than lower class people. This most likely resulted in larger, healthier members of the upper class. Therefore, mythology may have been used to legitimize malnutrition caused by social inequity. Finally, those chosen for sacrifice were mostly peasants and slaves from lower capulli. With little to live for and a looming concern of having nothing but darkness in the afterlife, the honor and comfortable existence promised to the sacrificed must have seemed like a desirable alternative to strife. If the sheer carnage and imposed power associated with sacrifice did not prevent upheaval, then this mindset potentially kept the masses at bay.
Importance of sacifice http://www.aztec-history.com/aztec-sacrifice.html
Aztec religion http://www.aztec-history.com/ancient-aztec-religion.html