The Origin of Caste, religious or social?

THE CASTE SYSTEM 
(Brahman, Kshatriyas, Vaisyas and Sudras)

In the Bhagavad Gita, Ch.4, Verse 13
The Lord says:
"The fourfold caste has been created by Me
according to the differentiation of Guna and Karma;"

In the Bhagavad Gita, Ch.18, verse 40 the
Lord says:
"There is no being on earth, or again in heaven among the
gods, that is liberated from the three qualities born of Nature."

Gita Ch. 18, V.41:
"Of Brahmanas, Kshtriyas and Vaishyas, as also the Sudras,
O Arjuna, the duties are distributed according to the qualities
born of their own nature."

So Caste system has it's origin in the hindu scriptures. It is originated ,supported and sustained by religion.