Theophylact of Ohrid
Catena Aurea · Johannesevangelium 8
Then said the Jews unto him. Thou art not yet fifty years old, and hast thou seen Abraham? Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am. Then took they up stones to cast at him: but Jesus hid himself, and went out of the temple, going through the midst of them, and so passed by.
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.