γράφειν καὶ συσσημαίνεσθαι
From LSJ
οὐκ ἔστι σιγᾶν αἰσχρόν, ἀλλ' εἰκῆ λαλεῖν → keeping silence is not shameful; speaking at random is (Menander)
Greek > English (Woodhouse)
sign and witness its being sealed, sign a document and witness its being sealed
