67. s.198.43; Hill, Sermons (III/11), 212; Dolbeau, Sermons, 398. (continued)
Ecclesial Reception of the Divine Life 215 the incarnation and the relationship between the church and Christ. Augustine justifies this parallel by quoting Eph. 5:31–32 and the Pauline metaphor of the church as the bride of Christ. After a brief discursus on true mediation, Augustine explains why Christ has come into the flesh:
And the reason why, for the sake of the purification that is effected by a mediator, the one who is equal to the Father wished to be the one mediator and himself become man was so that we through a related substance (because he is man) might attain to the supreme substance (because he is God).68
Divine mediation requires one who is naturally equal to the Father yet who has become humanly accessible by taking on our familiar substance (cognatam substantiam). In this is realized human purgation, explained here as approaching the supreme substance. This is a rather odd phrase for Augustine to employ here, ad summam substantiam (appearing nowhere else in his extant writings), yet it is used so as to form a contrast with both the cognatam substantiam and the lower regions (inferioribus) in which the human person would necessarily dwell without Christ. The Son has taken on flesh so as to communicate God's divinity and, as the whole of the sermon intends, Christ uses his mediatorial church to continue this mission of human elevation and transformation. We now turn to the two main channels of this grace, the sacraments of baptism and Eucharist.
This third section contains two distinct parts. Our overall aim is to understand the divine communion offered in and through the church. Was there a matter more pressing for the Bishop of Hippo than the integrity of God's church? Sanctity demands unity: holiness cannot fill the divided heart or a
68. s.198.49; Hill, Sermons (III/11), 218; Dolbeau, Sermons, 404: "Et ideo propter purgationem, quae fit per mediatorem, unus uoluit esse mediator et ipse homo fieri, qui aequalis est patri, ut per cognatam substantiam—quod est homo—ad summam substantiam—quod est deus—perueniremus."