The Enchiridion 44
44 In Speaking of Sin, the Singular Number is Often Put for the Plural, and the Plural for the Singular PL 40, 253
But even these latter are frequently said to die to sin, though undoubtedly they die not to one sin, but to all the numerous actual sins they have committed in thought, word, or deed: for the singular number is often put for the plural, as when the poet says, “They fill its belly with the armed soldier,” though in the case here referred to there were many soldiers concerned. And we read in our own Scriptures: “Pray to the Lord, that He take away the serpent from us.” He does not say serpents though the people were suffering from many; and so in other cases. When, on the other hand, the original sin is expressed in the plural number, as when we say that infants are baptized for the remission of sins, instead of saying for the remission of sin, this is the converse figure of speech, by which the plural number is put in place of the singular; as in the Gospel it is said of the death of Herod, “for they are dead which sought the young child’s life,” instead of saying, “he is dead.” And in Exodus: “They have made them,” Moses says, “gods of gold,” though they had made only one calf, of which they said: “These be thy gods, O Israel, which brought thee up out of the land of Egypt,”—here, too, putting the plural in place of the singular.
Figura, ἑτέρωσις, qua numerus accipitur pro numero. Sed ideo etiam ipsi peccato mori plerumque dicuntur, cum procul dubio non uni, sed multis peccatis omnibusque moriantur, quaecumque jam propria commiserunt, vel cogitatione, vel locutione, vel opere; quia etiam per singularem numerum pluralis numerus significari solet: sicut ait ille, « Uterumque armato milite complent » ; quamvis hoc multis militibus fecerint. Et in nostris Litteris legitur, Ora ergo ad Dominum, ut auferat a nobis serpentem ; non ait serpentes, quos patiebatur populus, ut hoc diceret: et innumerabilia talia. Cum vero et illud originale unum plurali numero significatur, quando dicimus in peccatorum remissionem baptizari parvulos, nec dicimus in remissionem peccati; illa est e contrario locutio, qua per pluralem significatur numerus singularis. Sicut in Evangelio Herode mortuo dictum est, Mortui sunt enim qui quaerebant animam pueri : non dictum est, mortuus est. Et in Exodo, Fecerunt, inquit, sibi deos aureos; cum unum vitulum fecerint, de quo dixerunt, Hi sunt dii tui Israel, qui eduxerunt te de terra Aegypti : et hic pluralem ponentes pro singulari.