First tip to Catholic News Service; full quote from John Allen, Jr.:

In terms of what we today can discover in this message, attacks against the pope or the church don’t come just from outside the church. The suffering of the church also comes from within the church, because sin exists in the church. This too has always been known, but today we see it in a really terrifying way. The greatest persecution of the church doesn’t come from enemies on the outside, but is born in sin within the church. The church thus has a deep need to re-learn penance, to accept purification, to learn on one hand forgiveness but also the necessity of justice. Forgiveness does not exclude justice. We have to re-learn the essentials: conversion, prayer, penance, and the theological virtues.

Pope Benedict XVI,
In-flight press conference en route to Portugal