It was the Sabbath - Some of the ancient rabbins taught, and they have been followed by some moderns, not much better skilled in physic than themselves, that the saliva is a cure for several disorders of the eyes; but the former held this to be contrary to the law, if applied on the Sabbath. See Lightfoot's Hor. Talm.

And it was the sabbath day when Jesus made the clay,.... Which was reckoned a violation of the sabbath, John 9:16, and was one reason why they had the man to the Pharisees to be examined, and why they were desirous of knowing where Jesus was:

and opened his eyes; by putting on the clay, and sending him to wash in the Pool of Siloam: nor did the miracle, nor the good done to the man, excuse with them, what they thought a breach of the sabbath.

It was the Sabbath day when (ἦν δὲ σάββατον ὅτε)

The best texts read, instead of ὅτε when, ἐν ᾗ ἡμέρᾳ on which day. Literally, it was a Sabbath on the day on which.

And it was the sabbath day when Jesus made the clay, and opened his eyes.

9:14 It was the sabbath. Saturday, the Jewish Sabbath. We have found in the case of the miracle at the pool of Bethesda how they were angered by his apparent violation of the day.

9:14 Anointing the eyes - With any kind of medicine on the Sabbath, was particularly forbidden by the tradition of the elders.

9:13-17 Christ not only worked miracles on the sabbath, but in such a manner as would give offence to the Jews, for he would not seem to yield to the scribes and Pharisees. Their zeal for mere rites consumed the substantial matters of religion; therefore Christ would not give place to them. Also, works of necessity and mercy are allowed, and the sabbath rest is to be kept, in order to the sabbath work. How many blind eyes have been opened by the preaching of the gospel on the Lord's day! how many impotent souls cured on that day! Much unrighteous and uncharitable judging comes from men's adding their own fancies to God's appointments. How perfect in wisdom and holiness was our Redeemer, when his enemies could find nothing against him, but the oft-refuted charge of breaking the sabbath! May we be enabled, by well-doing, to silence the ignorance of foolish men.