Academic linguists standardly deprecate artificial usage rules, for instance the rule about avoiding split infinitives, and prefer to study the rules which native speakers of a language apply naturally, without thinking about them. But this particular issue is a peculiar case where I think it is fair to say that there are only artificial rules, no "natural" alternative (unless perhaps some speakers add the extra apostrophe-s syllable across the board to all nouns ending in sibilants). Whichever published usage guide you consult will probably suggest slightly different rules. The one I treat as most authoritative is the Oxford Univ. Press "Hart's Rules" (I use the 2005 edition). To summarize as briefly as I can what it says:
When a personal name ends in an s or z sound, in the default case add apostrophe-s in writing and the /@z/ syllable in speech;
but in cases where an additional _s_ would cause difficulty in pronunciation, typically after longer names where the stress is not on the last or last-but-one syllable, it is allowable to make no change to the spoken form, and in writing add a bare apostrophe not followed by _s_; examples given are "Nicholas'[s], Lord Williams'[s] School". (I would add that the appearance of "naturalness" in the phrase "cause difficulty in pronunciation" is really spurious: no English-speaker would find it at all difficult in practice to say "Nicholas's", it's just that we conventionally treat such sequences as worth avoiding.)
In the particular case of "Jesus", Hart's Rules say that outside church liturgy "Jesus's" is usual but in church "Jesus' " is "an accepted archaism". However, the next rule treats classical names as special cases, and "Jesus" would be thought of by many as coming under that category, although Hart's Rules is thinking of Greek and Roman names (whereas Jesus is a Latinization of an originally Hebrew/Aramaic name). The rule given for classical names ending in _s_ or _es_ is that traditionally they take a bare apostrophe (and no distinct possessive form in speech), e.g. "Euripides', Herodotus', Mars', Erasmus'" (actually, if "Jesus" is not a "classical" name, I'm not sure why "Erasmus" counts as such). Having laid down the tradition treatment, Hart's Rules then says that it should be followed with long names, but with short names the apostrophe-s version is allowable, e.g. "Zeus' " or "Zeus's". And then it gives a suggestion for deciding which of these variants to opt for: in scientific "or other [sic] contexts" use apostrophe-s, e.g. "Mars's gravitational force", whereas when used for their original referents (I presume that is the idea), use the short version: "Mars' spear".
Got that? Then, an extra little twiddle: with French names ending in silent S in spelling, use apostrophe-s (in writing), e.g. Dumas's, Descartes's; but it doesn't say how to pronounce these forms (Hart's Rules is only about how to write, not how to speak) – I think probably people who know what they are doing would tend to pronounce one sibilant rather than two in these possessive forms, e.g. /-maz, -karts/.
All the above is about names of people. Apostrophe-s possessive forms also occur with place names (NB Hart's Rules assumes we are discussing British English, Americans also use the apostrophe form with nouns for inanimate objects, e.g. "the car's wheels", but we – English – would normally say "the wheels of the car", so that these apostrophe problems would not arise there). But the Rules essentially give up when it comes to place names and say "It is impossible to predict with certainty" whether to include an apostrophe in writing in a place name ending in S, e.g. "Land's End, Offa's Dyke, St James's Palace", but "All Souls College, Earls Court, St Andrews": you should just look up in a gazetteer or the like to see which usage is current. (This paragraph is principally about written forms, but of course "St James's Palace" might have been called "St James' Palace" and probably, at some point in its history, has been – but it isn't now.)
I think the above may be a longer response than you were expecting. I have been having a little fun with it, but I would stress that Hart's Rules is by no means the kind of publication that delights in complicating rules for the sake of complication. It aims to define a standard to enable people to achieve consistency in the details of their written usage, and normally its guidelines are sensible and straightforward. On this particular issue the considerable complexity (and vagueness) is only there because nothing more straightforward would reflect current English-language norms. That is why I say that on this issue there are really only artificial rules rather than natural rule(s).