If we pay no attention to the sense, this is a grammatically correct sentence. The problem is that "the virgin Mary" is a set phrase. Variation raises questions: "What does he mean? Why does he say it like that? Is he implying something? Does he have an ax to grind?"

*The Virgin Mary is Jesus' mother.

Jesus' vs. Jesus's: Wikipedia's "Apostrophe" article is good for this, because it references a variety of familiar authorities. If you favor a particular authority, you may find justification there for the spelling you prefer; but it seems both camps have plenty of ammunition.

If anyone cares, "Jesus'" is my way; my preferred authority is _The Elements of Style_; and I have the impression that for a long time "Jesus'" was the norm.

Thanks, changed according to your suggestions.

Perhaps even more interesting is Google's Ngram Viewer, which suggests that tradition is not only winning, but gaining ground. It's easy to be fooled by raw data, however. My bet is that regularization is going to win in the long run,
although "Jesus'" may be one of the last forms to succumb--at least in print. A great many of the books mentioning Jesus--except as an expletive--are "local" to a particular religious tradition and honor that tradition's norms. Intuition suggests there's many a popular preacher who writes "Jesus'" on his blog and says "Jesus's"--for clarity--in the pulpit.