Here the printer’s manuscript and the 1830 edition read suffer. The 1837 edition replaced suffer with succor, probably intentionally (although this change was not marked in 𝓟 by Joseph Smith in his editing for the 1837 edition). All subsequent editions have retained succor. It is quite possible that the original manuscript read succor and that scribe 2 of 𝓟 miscopied the word as suffer, especially since succor and suffer are orthographically similar. We should note that in one place in the original manuscript Oliver Cowdery spelled succor as succer (Alma 57:12). If the original manuscript had the same spelling of succer here in Alma 7:12, then the conjectured misreading as suffer by scribe 2 in the printer’s manuscript would be all the more plausible. Indeed, a spelling such as sucker would be even more susceptible to being misread as suffer (but there are no instances of that misspelling in the manuscripts).
Another possibility is that the scribe in 𝓞 misheard Joseph Smith’s succor as the phonetically similar suffer and thus wrote down suffer in 𝓞. It’s also possible that Joseph himself misread succor as suffer as he dictated the text. But no matter when suffer entered the text here in Alma 7:12, there was probably some influence from the preceding text, which refers to Christ’s suffering:
In fact, the word suffering, found near the beginning of verse 11, could have prompted the replacement of succor with suffer later on in verse 12.
Elsewhere in the text, there are four more occurrences of the verb succor (which means ‘to help, relieve’):
On the other hand, when the direct object for the verb suffer is a human, the typical meaning for suffer is ‘to allow’, as in 3 Nephi 16:14: “I will not suffer my people ... to go through among them”. Nor is there any evidence from the Oxford English Dictionary to suggest that suffer originally had a meaning that would work more reasonably here in Alma 7:12. The earliest reading (“how to suffer his people according to their infirmities”) does not make much sense, especially in context. The most reasonable emendation is succor.
There are two instances of the verb suffer elsewhere in the text that one might suppose could be mistakes for succor:
The OED, however, indicates that one meaning for suffer (now rare and archaic, according to the OED) is ‘to tolerate, put up with’ (see definition 12 under the verb suffer). And this is precisely the meaning for these two occurrences of the verb suffer in Helaman 13. On the other hand, the negative meaning ‘to tolerate, put up with’ will not work for the instance of suffer in Alma 7:12; it is clear that this passage does not mean that ‘he may know according to the flesh how to tolerate his people according to their infirmities’.
Summary: Accept in Alma 7:12 the 1837 emendation of suffer to succor since only succor makes sense in context; the aural or visual similarity between the two words, plus the preceding occurrence of suffering in verse 11, seems to have caused succor to be accidentally replaced by suffer early on in the transmission of the text.