John 7:21

ἓν ἔρ. ἐπ. I did one work; the healing at Bethesda, which (He reminds them) excited the astonishment and indignation of all, not of the rulers only, as being wrought on the Sabbath. Ἕν, a single work, in contrast to frequent circumcisions on the Sabbath, or possibly to the many works which excited comparatively little attention: ἕν balances πάντες, one act sets all in amazement.

Many modern editors add διὰ τοῦτο from John 7:22 to this verse; ‘and ye all marvel on account of this.’ But this is cumbrous, and unlike S. John, who begins sentences with διὰ τοῦτο (John 5:16; John 5:18; John 6:65; John 8:47; John 10:17; John 12:18; John 12:39) rather than ends them with it.