Later sources extol the Taiping as liberators and peasant heroes who overthrew the landlord class. But at the time, was that purely what the average Taiping supporter believed in, or were they really invested in Hong's religious vision? Did they believe Hong was the younger brother of Jesus?
Short answer: We can't be absolutely sure, although I'm inclined to believe so.
Long answer: It depends on how much you're willing to buy into Western accounts and Taiping government activities and how far you're willing to extrapolate from them, although in my opinion there is enough evidence to suggest that there was quite a bit of genuine religious feeling.
One of the great paradoxes about the Taiping Heavenly Kingdom is the extremely high literacy of its leadership, in contrast with its almost entirely peasant support base. As such, whilst we have numerous Taiping sources, all were produced by either leading generals or the bureaucracy, and relate to government policy, military affairs or theology. What we don't have is any sort of account from an ordinary peasant in Taiping territory. One of the few memoirs we have from an ordinary civilian is that of Zhang Daye from Shaoxing, Zhejiang, and he was a mere child of seven in a heavily-contested piece of territory, and his lack of appreciation for Taiping theology tells us very little at all. As such we really cannot rely on much other than Western correspondence and memoirs, plus inferences from a few statistics, to try and assess the depth and breadth of religious feeling in Taiping territory.
That is not to say that there is nothing at all from the Taiping side that would suggest a degree of religious devotion, but it is very limited. First of all, the Taiping Heavenly Kingdom was founded seven years after the God-Worshipping Society, whose members had grown to anywhere up to 50,000 by 1851, and it is hard to believe that they joined the society purely out of economic self-interest at this stage. We can certainly ascertain that the Taiping leadership were keen to promote religiosity given their stipulations for weekly church services and strict observance of the Sabbath in the Land System of the Heavenly Dynasty (1852). A pamphlet issued some time in either late 1855 or early 1856, detailing incidents of the voice of God speaking through Yang Xiuqing, includes one incident of God speaking through Yang to order corporal punishment upon Hong Xiuquan. That this was taken seriously (Hong being Yang's superior under normal circumstances) is especially indicative of how seriously the Taiping took their religion.^1
However, what these latter two sources have in common is that they fall under the umbrella of what Franz Michael termed 'Nankingology' – that is, they describe either the ideal situation and/or the situation in the Taiping capital at Nanjing, and so should not be seen as indicative of the reality of the Heavenly Kingdom elsewhere.
The issue of Nankingology remains with many of our Western sources. Until 1860 there was little Taiping territory between Nanjing and Shanghai, and missionaries rarely travelled any further than the immediate surroundings of Nanjing, so the vast majority of our reports on Taiping belief are again concentrated in this area. Take the American Methodist Charles Taylor, who expressed great amazement at the devoutness of Taiping believers in Nanjing in 1853,^2 or the Welsh Congregationalist Griffith John, who again asserted the devotion of the Taiping in 1860.^3 Even in his most defeatist letter in late 1861, the Southern Baptist Issachar Roberts only remarked upon the heretical nature of Taiping beliefs, but still noted their being sincerely held.^4 Yes, these indicate that there was strong religious feeling in Hong's capital, but what about the outer stretches of Taiping control? What of those just upriver from Anqing or those in newly-occupied Jiangsu and Zhejiang?
Unfortunately, here I am only aware of a few sources on the matter, and many are rather problematic in their own right. One former captive of the Taiping in Zhejiang, who returned to Qing hands in 1862, reported that church services were held twice a month rather than once a week, although their content as described by him appear little changed from those of earlier accounts.^5 On the other hand, Augustus Lindley, admittedly an unabashedly pro-Taiping polemicist, recalled a Taiping Christmas feast in Jiangsu at the end of 1863 that was done to the fullest extent possible despite a generally bleak military situation.^6 The Taiping presses were highly active in printing tracts that saw widespread distribution in Qing territory – but this is something more indicative of state policy than popular belief, and given the lack of success by Christian pamphlets one can question the effectiveness of the replication of their techniques by the Taiping.^7 Reilly (2004) makes much of estimates of the geographical origin of Nanjing residents as well records of those of people on Taiping army rolls, which do indicate a very broad distribution of provincial origin in which the original God-Worshipping core of Guangdong and Guangxi made up only a tiny proportion – the implication being that the existence of a large number of non-south coast followers would suggest successful conversion in the interior, especially as many would have to have emigrated from their home provinces as the Taiping army moved on.^8 However, an alternative interpretation could be that they at most indicate that many people from many provinces were sufficiently pro-Taiping to migrate to Nanjing for any number of reasons, not only religious, and that the Taiping had a wide base of conscription. Moreover, the representativeness of the capital city and two army units numbering 27 and 1000 men respectively can be called heavily into question, even if they are the only figures we have. Nevertheless, taking all these various bits and bobs into account, it can be said that there was at least a reasonable quantity of Taiping devotees, just that neither the actual nor proportionate number can be ascertained.
Whilst the Taiping religion died with the Heavenly Kingdom, it is difficult to infer from this that the Taiping were never that invested in their religion. Rather, it fits with a general trend where, in the absence of some sort of actual structured organisation, heterodoxies simply tended to dissipate, and reflects more on the highly successful suppression campaign conducted by the Qing than anything else.
Sources, Notes and References