There is a major difference between a critic and a prophet. Critics stand outside a system and mock it. Prophets remain clear-eyed and conscientious, inside a sinful system, and love it anyway. It is easy to condemn the country, for instance. It is possible to criticize the church. But it is prophetic to love both church and country enough to want them to be everything they claim to be—just, honest, free, equal—and then to stay with them in their faltering attempts to do so, even if it is you yourself against whom both church and state turn in their attempts to evade the prophetic truth of the time.
The French papacy at Avignon did not want to hear the call of Catherine of Siena but, in the end, she prevailed and they returned the Holy See to Rome. The powers that be did not want to hear Joan of Arc and killed her to silence her, but in the end, her prophetic word outlasted them all. Neither church nor state wanted to hear Dorothy Day and Thomas Merton in their pleas for the poor and their prophetic cries for peace, but in end, it is their message that expose the secularization of the church, that haunt it at the turn of every gospel page, that challenge it to this day and that have marked its best presence in our times.
The function of the prophet is not to destroy. The function of the prophet is to expose whatever cancers fester beneath the surface so that what is loved can be saved while there is yet time.
To claim, then, that to criticize the government is treason, to insist that to criticize the church is disunity, may be the greatest perfidy and the deepest infidelity of them all. It is a prophet’s lot to risk the two so that what is worth loving can be lovable again.
--from Joan Chittister: Essential Writings (Orbis)