John Gill

Jesus answered and said unto them,.... Taking no notice of their passion, reproach, and blasphemy; but proceeding upon the thing he had in view, and which he was determined to reassume, and vindicate himself in; I have done one work; that is, on the sabbath day; meaning, his cure of the man that had had a disorder eight and thirty years, who lay at Bethesda's pool; which single action, they charged with being a breach of the sabbath, he mentions with a view to their many, and daily violations of it: and ye all marvel; at it, as a thing unheard of, as a most shocking piece of iniquity, as an intolerable evil; wondering that any man should have the front, to bid another take up his bed and walk, on the sabbath day: they did not marvel at the miracle that was wrought; but were amazed, offended, and disturbed, at its being done on the sabbath day.