G4258–προαμαρτάνω–proamartanō

and that upon re-visiting you I may be humbled by my God in your presence, and may have to mourn over many whose hearts still cling to their old sins, and who have not repented of the impurity, fornication, and gross sensuality, of which they have been

προημαρτηκότων proēmartēkotōn “having sinned before”

Those who cling to their old sins, and indeed all of you, I have forewarned and still forewarn (as I did on my second visit when present, so I do now, though absent) that, when I come again, I shall not spare you;

προημαρτηκόσιν proēmartēkosin “having sinned before”