The title “high priest”, however, is not used by Ignatius, and in the extant Christian literature first occurs in Tertullian, _On Baptism_ 17 (_ca._ 205); Hippolytus also uses “high-priesthood” of the episcopal office in Philosophumena, Proem. 6. Similarly Tertullian calls the presbyters “priests” in his _Exhortation to Chastity_ 7, 11 (_ca._ 210), and in 9. 2 of our treatise Hippolytus describes their work as “priesthood”. This appearance of sacerdotal titles for Christian ministers—something that is foreign to the New Testament—was a consequence of the adoption of sacrificial terms for Christian worship:[159] sacrifices are offered by priests. So Didache 13. 3 describes the prophets as “your high priests” (compare 15. 1), while Ignatius (_Philadelphians_ 4) writes “one altar, as one bishop”. Consequently it is more than probable that “high priest” and “priest” were in common—although by no means universal—use among Christians by the middle of the second century. Hippolytus’s distrust of innovations corroborates this; apart from anti-modalist additions the terminology of his consecration prayer can scarcely be thought to depart much from the forms in use in his younger days. Otherwise the bishop is said to “feed the flock”, a New Testament phrase[160] that was of course traditional; to Hippolytus it would include both correct teaching of doctrine and faithful administration of the sacraments. Since in Philosophumena IX, 7 he inveighs fiercely against Callistus’s claim to absolve grave sins, “to remit” here can refer only to minor offences. “To assign the lots” strictly construed would mean “to appoint the clergy”, but compare on 9. 1. “To loose every bond” is probably only a traditional liturgical generality. THE CHRISTIAN “SACRIFICES”