Laudator Temporis Acti

2 Thessalonians 3:10 (King James Version):

For even when we were with you, this we commanded you, that if any would not work, neither should he eat.

καὶ γὰρ ὅτε ἦμεν πρὸς ὑμᾶς, τοῦτο παρηγγέλλομεν ὑμῖν, ὅτι εἴ τις οὐ θέλει ἐργάζεσθαι, μηδὲ ἐσθιέτω.

Erasmus, Adages II ix 88 (tr. R.A.B Mynors):

Ni purges et molas, non comedes
Unless you clean and grind, you'll have nothing to eat

Ἂν μὴ καθάρῃς καὶ ἀλέσῃς, οὐ μὴ φάγῃς, Unless you clean and grind, you'll have nothing to eat. No food, that is, will come your way unless you also contribute your own energy. Ceres is said to have used these words when she taught Triptolemus the use of grain. It looks like an iambic line borrowed from some poet, but it is corrupt; it will scan if you read κἀλέσῃς. It can be adapted to a very different context: 'Your intelligence will be no use to you unless you use it,' 'Princes' favour will be useless unless you know how to behave,' 'It will be no help to have acquired a good teacher if you don't keep awake yourself.' Recorded by Diogenianus [5.17].

As ἢν μὴ καθάρῃς κἀλέσῃς, οὐ μὴ φάγῃς, this is Tragica Adespota, fragment 134 Nauck. καθάρῃς here = winnow, sift.