How does the division of purusha's body give justification for the social status of the castes in india?

The division of Purusha's body gives justification for the social statuses of India's castes because the division explains the sacrifices he is performing, and how he is giving away his body for the people.

The following lines of the Rig Veda relate to the sacrifice of the primeval being Purusha: "The Brahmin (priests; highest social class) was his mouth, of both his arms was the Kshatriya (warriors and aristocrats; second highest social class) made. His thighs became the Vaishya (cultivators, artisans and merchants; second lowest social class), from his feet the Shudra (landless peasants and serfs; lowest social class) was produced".

This shows the importance of all the castes, but that the higher levels are more glorious than others. It shows the people their worth in society and how they contribute to it.