Gopalasutta 6.3

6.3

yatvādhikaraṇamenaṃ cakkhundriyaṃ asaṃvutaṃ viharantaṃ abhijjhādomanassā pāpakā akusalā dhammā anvāssaveyyuṃ, tassa saṃvarāya na paṭipajjati; na rakkhati cakkhundriyaṃ, cakkhundriye saṃvaraṃ nāpajjati.

Since the faculty of sight is left unrestrained, bad unskillful qualities of covetousness and displeasure become overwhelming. They don’t practice restraint, they don’t protect the faculty of sight, and they don’t achieve its restraint.