6 “Judge not according to personal appearance, but judge righteous judgment.” What is this? Just now, you who by the law of Moses circumcise on the Sabbath day are not angry with Moses; and because I made a man whole on the Sabbath day you are angry with me. You judge by the person; give heed to the truth. I do not prefer myself to Moses, says the Lord, who was also the Lord of Moses. So consider us as you would two men, as both men; judge between us, but judge a true judgment; do not condemn him by honoring me, but honor me by understanding him.
For this He said to them in another place: “If you believed Moses ye would certainly believe me also, for he wrote of me.” But in this place He willed not to say this, Himself and Moses being as it were placed before these men for judgment. Because of Moses' law you circumcise, even when it happens to be the Sabbath day, and will you not that I should show the beneficence of healing during the Sabbath? For the Lord of circumcision and the Lord of the Sabbath is the same who is the Author of health; and they are servile works that you are forbidden to do on the Sabbath; if you really understand what servile works are, you sin not.
For he that commits sin is the servant of sin. Is it a servile work to heal a man on the Sabbath day? You do eat and drink (to infer somewhat from the admonition of our Lord Jesus Christ, and from His words); at any rate, why do you eat and drink on the Sabbath, but because that what ye do pertains to health? By this ye show that the works of health are not in any wise to be omitted on the Sabbath. Therefore “do not judge by person, but judge righteous judgment.” Consider me as you would a man; consider Moses as a man: if you will judge according to the truth, you will condemn neither Moses nor me; and when you know the truth you will know me, because I am the Truth.
Source: Tractates on the Gospel of John (New Advent)