CCC 1327

In brief, the Eucharist is the sum and summary of our faith: "Our way of thinking is attuned to the Eucharist, and the Eucharist in turn confirms our way of thinking."¹³⁸ St. Irenaeus, Adv. haeres. 4, 18, 5: PG 7PG — Patrologia Graeca (Migne)/l, 1028.