Dear readers,

OP used the term "Christian" where a more specific term such as "Protestant" (or something even more specific) might have been more appropriate. There's no need to make a post pointing that out (though you're of course welcome to point that out as part of a comprehensive and in-depth answer).

There's also no need to challenge OP on whether or not this idea actually is correct. The idea exists - Max Weber wrote a famous work on this topic - and OP is asking for where the idea comes from. if the idea is incorrect, that can be pointed out as part of a comprehensive and in-depth answer.

Though I cannot answer the question about the origins of this idea, I can point out a particularly useful example in American history. The minister Russell Conwell (the founder of Temple University) gave an extremely influential sermon called Acres of Diamonds to thousands of audiences that essentially proclaimed that the rich were rewarded by God for being rich while the poor were punished for their shortcomings. It was delivered to numerous audiences during the Gilded Age and told people their worldly salvation was dependent on their own willingness to reform themselves to be more godly. Once people became more virtuous, then God would give them wealth as a reward.

Max Weber wrote in his influential book The Protestant Ethic and the Spirit of Capitalism that a certain work ethic associated with Protestantism specifically led to Protestant success in worldly, money-making endeavors, pointing out that mercantile professions were pursued by Calvinists who believed in predestination and looked for some sort of sign to indicate whether they were saved.

Another question: Wasn't Jesus very poor, and was it said that being poor was equal to walking in the footsteps of Jesus?

Side question. Is this mentality tied to the Prosperity Gospel?

Just wanted to point out that this idea predates Christianity, and I assumed it was a main theme in human history that the rich must be divinely blessed. A good example of this ancient idea is the Book of Job. Job's three friends are pretty much beating this dead horse: you must have sinned, because God stole away all your wealth and children. This thought of worldly blessing as an evidence of spiritual righteousness is also the idea Jesus confronts concerning the Tower of Siloam (sp?). So prosperity gospel Christians have a long legacy of this idea to draw upon.

About 100 years ago the German sociologist Max Weber theorized that one of the causes for the rise of Capitalism was Protestantism (specifically ascetic Protestantism). It's not so widely accepted today (although much debated), but I think it can offer a possible explanation to OP's question.

To understand the Weber Thesis, we need first to recall medieval Catholicism. So, for more than a 1000 years, this is basically (but not completely) the only time of Christianity in western Europe. most people were secular Christian (they were not called Catholic, as there was no other type to speak of), and a large minority were clergy (monks, friars or priests). According to Catholic theology of the time (and I believe today as well), A believer spends his life gaining or loosing "points" - by doing righteous of pious deeds (of committing sins) - and upon his death, he is judged and accordingly sent to heaven ("salvation") or to hell ("damnation") (or the purgatory). A believer can also redeem himself by committing pious acts (pilgrimage, penance) that counter act his sins (for a time, mostly in the 14-15th century a believer could buy some "points" for himself or others. in part, this might have helped stir the genesis of the Reformation).

Now, Protestants, and mostly Calvinists (the branch of early Protestantism founded by the Frenchman Jean Calvin, and out of which a great extent of modern American Protestant churches rose) had a different theology. Calvin was an adherent of Predestination. This is the belief that your whole life have been per-determained by God in the beginning of time. All your righteous and evil deeds are not your choice, but you destiny. And thus, God has already decided of you are to be saved or doomed when you die. Theologically, the Calvinist can only observe and try to assess his destiny. He can only guess if God has chosen him. However, Calvin said that the believer might have some clue. For example, if he is chosen by God for salvation, he is more likely to be kind, righteous and successful. In practice, this gave a huge motivation for Calvinists to be righteous and successful, so they could reassure themselves of their salvation.

Now, Weber argued, that Protestants and Calvinists in particular, tended to strive for business success, while on the other hand, to maintain a modest (=pious) lifestyle. this lead to an increase in capital that could be invested to gain more "success" (while a successful catholic might just spend this money, lest say), and voilà: Capitalism. Now, we can argue on the same lines, that modern Protestants might identify economic success with spiritual virtue for the same reason: It stems from the teaching of Calvin. This success is an evidence to the "election" (this is the theological term) of the wealthy person, and therefore attests to his spiritual value in the eyes of God.

Weber, Max. The Protestant Ethic and the Spirit of Capitalism https://en.wikipedia.org/wiki/The_Protestant_Ethic_and_the_Spirit_of_Capitalism

Edit: Totally missed to opportunity to use "karma" instead of "points".

As the Moderator pointed out (also read his post to improve your good manners while on reddit), "Protestant" would be a more suiting term. In fact, who actually believe in "ascension" through work are Lutherans and Calvinists.

Since believers offer something to God in order to honor it, be it money (for the church to use it to help people in need) or others (emotions or even the withstanding of pain in the name of God). Lutherans were offering money, profit of their work, and such meant more people could be helped. From there started the belief that God would compensate those who helped by giving them more money than what they donated, and obviously that would come through their work. The more you are succesfull the more money you can give the more God compensates you. Also, they would be offering the pain and efforts of their hard-work to God, and the profit would be its way to tell them it appreciated their act.

On the other hand, there are Calvinists who believed everything was decided by God from the day you were born. Of course if you were in God's favor, your life would be good and without troubles; whereas if God didn't love you, your life would be terrible and full of obstacles. Therefore, succesfull people would be those in favor of God: why did God choose them? Because they would never sin and would be models for society. The others are abandoned by God because they would sin so much in life that God just gave up on them and gave them nothing