Albert Barnes Commentary John 7:21

"Jesus answered and said unto them, I did one work, and ye all marvel because thereof." — John 7:21 (ASV)

One work. The healing of the man on the Sabbath, John 5.

You all marvel. You all wonder or are amazed, and particularly that it was done on the Sabbath. This was the particular ground of astonishment, that he should dare to do what they esteemed a violation of the Sabbath.