10 “What do you seek?” They said unto Him, “Rabbi (which is to say, being interpreted, Master), where dwellest Thou? He says to them, Come and see. And they came and saw where He dwelt, and abode with Him that day: and it was about the tenth hour.” Do we think that it did in no wise pertain to the evangelist to tell us what hour it was? Is it possible that he wished us to give heed to nothing in that, to inquire after nothing? It was the tenth hour. That number signifies the law, because the law was given in ten commandments.
But the time had come for the law to be fulfilled by love, because it could not be fulfilled by the Jews by fear. Hence the Lord says, “I am not come to destroy the law, but to fulfill.” Suitably, then, at the tenth hour did these two follow Him, at the testimony of the friend of the Bridegroom, and that He at the tenth hour heard “Rabbi (which is interpreted, Master).” If at the tenth hour the Lord heard Rabbi, and the tenth number pertains to the law, the master of the law is no other than the giver of the law.
Let no one say that one gave the law, and that another teaches the law: for the same teaches it who gave it; He is the Master of His own law, and teaches it. And mercy is in His tongue, therefore mercifully teaches He the law, as it is said regarding wisdom, “The law and mercy does she carry in her tongue.” Do not fear that you are not able to fulfill the law, flee to mercy. If you can not fulfill the law, make use of that covenant, make use of the bond, make use of the prayers which the heavenly One, skilled in the law, has ordained and composed for you.
Source: Tractates on the Gospel of John (New Advent)