The number here signifies the law, which was composed of ten commandments. The time had come when the law was to be fulfilled by love, the Jews, who acted from fear, having been unable to fulfil it, and therefore was it at the tenth hour that our Lord heard Himself called, Rabbi; none but the giver of the law is the teacher1 of the law.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Tr. vii. c. 10