Posted November 7, 2005 - 15:42
English uses the possessive clitic -'s to mark possession. When it is used after a plural noun ending in -s it is reduced to an apostrophe ('). Thus, bus's means 'that which belongs to a bus', but buses' means 'that which belongs to a number of buses'. However, traditionally, certain classical, but not modern, names that end in -s also use the apostrophe-only clitic to mark the possessive. This is the case with Jesus, where the possessive is Jesus'. The two words, with and without an apostrophe, are pronounced exactly the same. Only the context determines whether the possessive is being used or not in speech. However, Jesus's, the form that would be dictated by strict application of the standard rule, is also seen today.
If it is ever needed, the plural (belonging to a number of Jesuses) would be Jesuses'.