If Marx found deism and Protestantism to be "the most fitting form of religion" for capitalism, that is not surprising, for those were the varieties of religion embraced and developed by the leaders of nations where social relations of capitalism originated and developed first. Likewise in the sphere of secular philosophy, liberalism, with "its cultus of abstract man," is the most fitting form of it. If Islam, (the old-fashioned) Judaism (of Jews of Russia, Eastern Europe, and the Middle East among others), Catholicism, Hinduism, Buddhism, American Indian spirituality, and so forth did not fit capitalism as well as deism and Protestantism in the 19th century, that is not surprising either, for those were religions of peoples whose social relations were less capitalist than those of predominantly Protestant Christian nations at that time.
That's at the highest level of abstraction, though. In reality, all faiths come in great variety and change over time. Engels was more interested in sociological, anthropological, and historical investigations of varieties of culture, including religion, than Marx was.
Engels, as a matter of fact, argued that early Christianity and many medieval Christian revolts were precursors to modern working-class mass movements, and he found many material and spiritual parallels between Christianity and socialism, which he appears to have regarded as the greatest universalist mass movements, the latter the heir to the former: "The parallel between the two historic phenomena forces itself upon our attention as early as the Middle Ages in the first risings of the oppressed peasants and particularly of the town plebeians" (Frederick Engels, "On the History of Early Christianity," <http://www.marxists.org/archive/marx/works/download/Marx_On_the_Histsory_of_Early_Christianity.pdf>).
Among the hilarious material parallels he found is that both had trouble collecting contributions and attracted multitudes of flakes in the beginning. :->
And just as all those who have nothing to look forward to
from the official world or have come to the end of their tether
with it -- opponents of inoculation, supporters of
abstemiousness, vegetarians, anti-vivisectionists,
nature-healers, free-community preachers whose communities
have fallen to pieces, authors of new theories on the origin of
the universe, unsuccessful or unfortunate inventors,
victims of real or imaginary injustice who are termed
"good-for-nothing pettifoggers" by all bureaucracy,
honest fools and dishonest swindlers -- all throng to
the working-class parties in all countries --
so it was with the first Christians. (Engels,
"On the History of Early Christianity")
Engels also commented on Mahdi revolts, too, in the same essay, though only in a footnote. He contrasted Mahdi revolts with Christian revolts and believed that the former, "even when they are victorious, . . . allow the old economic conditions to persist untouched," whereas the latter were "attacks on an economic order which is becoming antiquated" (Engels, "On the History of Early Christianity"). The Mahdi revolts of Engels's time were indeed like that: even victorious Mahdi revolts could not establish a new revolutionary order that would endure and develop for a long time.
The irony is, though, that the only victorious religious revolution in history turned out to be an Islamic, not Christian, one. Engels said that among early Christians there were "a feeling that one is struggling against the whole world and that the struggle will be a victorious one; an eagerness for the struggle and a certainty of victory which are totally lacking in Christians of today and which are to be found in our time only at the other pole of society, among the Socialists" (Engels, "On the History of Early Christianity"). Hegel's World-Spirit, however, has overtaken atheist socialists and communists, leaving an Islamist to say, "The Zionist regime will be wiped out soon _the same way the Soviet Union was_, and humanity will achieve freedom" (emphasis added, Arash Norouzi, "'Wiped off the Map': The Rumor of the Century," 18 January 2007, <http://democracyrising.us/content/view/736/164/>). Today, secular socialists and communists have no sense of "certainty of victory." Who today has confidence that secular socialists and communists once had? Islamsits of the Middle East and Christian socialists* of Latin America. "Behind Ismail was another poster of Nasrallah. 'He promised a victory, and a victory is coming, just like he said'" (Anthony Shadid, "With Street Protests, Hezbollah Gambles in Quest for Dominance," 6 December 2006: A14, <http://www.washingtonpost.com/wp-dyn/content/article/2006/12/05/AR2006120501292_pf.html>).
History didn't end when Engels thought that socialism, inheriting the revolutionary legacy of its religious precursor, would soon turn the world upside down, workers fighting their "lutte finale" as L'Internationale prophesied. In the end, the world may or may not go the way of the faithful of Latin America and the Middle East, but I am certain that their faith, not the faith in Godless socialism and communism, will be the faith of oppressed masses of the world in the near future.
* <http://www.ipsnoticias.net/nota.asp?idnews=40199> POLÍTICA-VENEZUELA: Con el Jesús en la boca Por Humberto Márquez
CARACAS, feb (IPS) - ¿Era Cristo socialista? "Claro que sí, el más grande de la historia", ha dicho el presidente de Venezuela, Hugo Chávez, ante críticas de jesuitas y respaldos que llegan desde los adherentes a la Teología de la Liberación.
El marco que sostiene la nueva polémica en Venezuela es la directiva del gobernante para avanzar aceleradamente hacia lo que llama "socialismo del siglo XXI", proyecto que ha cargado de adjetivos como "bolivariano, humanista, endógeno, indoamericano y cristiano". -- Yoshie <http://montages.blogspot.com/> <http://mrzine.org> <http://monthlyreview.org/>