Plato, Laws 930b

τὴν συνοίκησιν ποιεῖσθαι· ὅσοι δʼ ἂν ἱκανῶν ὄντων παίδων, τῆς συγκαταγηράσεως ἕνεκα καὶ ἐπιμελείας ἀλλήλων τὴν διάζευξίν τε καὶ σύζευξιν ποιεῖσθαι χρεών. ἐὰν δὲ τελευτᾷ γυνὴ καταλείπουσα παῖδας θηλείας τε καὶ ἄρρενας, συμβουλευτικὸς ἂν εἴη νόμος ὁ τιθέμενος, οὐκ ἀναγκαστικός, τρέφειν τοὺς ὄντας παῖδας μὴ μητρυὰν ἐπαγόμενον· μὴ δὲ ὄντων, ἐξ ἀνάγκης γαμεῖν, μέχριπερ ἂν ἱκανοὺς γεννήσῃ παῖδας τῷ

they must form unions with a view to children; but if they have children enough, then the object both of the separation and of the new union should be to obtain companionship and mutual assistance in old age. If a man’s wife dies, leaving both male and female children, there shall be a law, advisory rather than compulsory, directing the husband to rear the children without introducing a step-mother; but if there be no children, the widower must of necessity marry, until he has begotten children sufficient alike for his household and the State.