Concerning the first point he does two things: first, he places the sacrament in the genus of signs; second, he defines signs, at A sign is a thing which, over and above the form which it impresses on the senses, causes something else to come into the mind through itself.
Et circa haec, duo facit: primo ostendit differentiam inter sacramenta veteris et novae legis; secundo determinat de quodam sacramento veteris legis, quod maxime cum sacramentis novae legis communicat, ibi: fuit autem inter illa sacramenta sacramentum quoddam, scilicet circumcisionis, idem conferens remedium contra peccatum quod nunc baptismus praestat.