Two Cities

Cognovit autem Cain uxorem suam, et concepit, et peperit Henoch, et aedificavit Cain civitatem Quid ergo sibi per figuram vult, quod impiorum progenies civitatem in ipsa mundi origine construxit? Nisi quod noveris impios in hac vita esse fundatos, sanctos vero hospites esse et peregrinos. Unde et Abel tanquam peregrinus in terris, id est, populus Christianus non condidit civitatem. Superna enim est sanctorum civitas, quamvis hic pariat cives, in quibus peregrinatur, donec regni ejus tempus adveniat. Sanctus Isidorus Hispalensis, Mysticorum Expositiones Sacramentorum Seu Quaestiones In Vetus Testamentum, In Genesin, Caput VI Source: Migne PL 83.227a

Cain knew his wife, and she conceived and gave birth to Henoch, and Cain built a city. 1 What, then, does he wish to convey with this figure, that the offspring of the wicked built a city at the beginning of this world? What but that you understand that the wicked are established in this life and the holy are as guests and passers by. Whence Abel also was a wanderer on the earth, that is, the Christian people have not founded a city here. For the city of the holy is above, 2 although it brings forth citizens here, among whom it wanders about, until the time of its kingdom shall come. Saint Isidore of Seville, Expositions of Sacred Mysteries or Questions on the Old Testament, On Genesis, Chapter 6 1 Gen 4.17 2 Heb 12.22-24, Apoc 21.2-4