Christ was then thirty-three years old. Why then do they not say, Thou art not yet forty years old, instead of fifty? A needless question this: they simply spoke as chance led them at the time. Some however say that they mentioned the fiftieth year on account of its sacred character, as being the year of jubilee, in which they redeemed their captives, and gave up the possessions they had bought.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).