There are some religions that have created differentiations among their members, often linked to class. For example, the higher a person was in the religion, the higher in social class. More respected members of the religion would have a higher place in society.
Social status established on the basis of religion is very prevalent in what is called The Bible Belt--This topic is satirized and documented both in books. In small Southern towns, the higher socio-economic people are usually Episcopalian, then the next on the social ladder attend the First Methodist Church--the largest one in town. The largest Baptist Church then lines up for equal, or almost equal treatment. (The Baptists and Methodists sometimes reverse position.)
Because most of the residents from the South are descended from the British, they retain from the Puritans the animosity toward Catholicism, so anyone who is Catholic ( a Papist) is often disparaged and not always hired for jobs in small towns, at least.
Religion may be linked to social inequality if the religion being practiced is not the dominant religion in a particular culture or society. This is related to cultural and societal norms. A norm is what is regarded as being standard or typical. Cultures and societies have various different types of norms. If a religious norm of a particular culture or society is to be a Christian and someone who practices another religion moves into the society, they may be looked down upon and seen as socially unequal simply because they do not fit the general standard.
Your question seems to relate to the ideas of thinkers such as Karl Marx, who famously stated that "Religion is the opiate of the masses." What he meant by this is that in his opinion religion acted like a drug to the poor masses in society, preventing them from seeing the reality of their poverty-stricken situation and making them content with their lot in the world. Religion thus allowed the masses to be exploited and to perpetuate systems of inequality that gave incredible riches to a small minority in society and kept the majority in often dire straits. Religion can do this through its teaching on respect and reverence towards leaders and acceptance of our lot in the world. Christianity, for example states in the Bible that we are to pray for our leaders and not rebel against them. This of course would leave people open to exploitation at the hands of the ruling elite and it also encourages the masses to accept the status quo and not ask the bigger underlying questions such as why do so few people have so much wealth?
If you want a modern day example you can look at Hinduism and its emphasis on caste. This gives specific groups of people given roles in life that they are fated to follow. The dalits, "the untouchables", for example are rejected by all society and considered the underclass, which relegates them to a position of povery and inequality from their birth thanks to this religion.
The Original teachings of all major religion never supported the social inequality.All major religions were basically true but with the passage of time their teachings became corrupted by human manipulations. And the main purpose of all religions was to make people believe in the unity of God. So there is no major religion in the world the original teachings of which ever supported the social inequality.
None of the major religions of the world support social inequality in principle. However, people following a particular religion do often look down upon people of other religion. Also people do often favor people of their own religion in preference over people of other religions. Because of this in a society comprising of people from different religions, the people of dominant religion may become a privileged class of people. In this way, religion may breed and encourage social inequality