"'Tis not enough, because they had not baptism Which is the portal of the Faith thou holdest;"

(Canto 4, lines 35-36)

Baptism is the first of the seven Sacraments of the Roman Catholic Church (Baptism, Confirmation, Holy Eucharist, Penance, Anointing of the Sick, Holy Orders, and Matrimony) and therefore here termed the "portal" of the faith.