One of my favorite passages comes from his remarkable book entitled The Need and the Blessing of Prayer. For those who feel themselves peeling off from the Church, being pulled away because of disgust or anger and hurt, betrayal and hypocrisy, I offer you Rahner's words. If you feel isolated, excluded, or thrust to the margin...do not take this necessarily as a sign of God's calling your elsewhere. Perhaps this is a moment of dark grace, a purgative moment meant to offer an opportunity to come to know God better so that you might claim a prophetic role in the Church.
...Become aware that God has been expecting you for quite some time in the deepest dungeon of your rubbled-over heart. Become aware that he has been quietly listening for a long time whether you, after all the busy noise of your life, and all the idle talk that you called your illusion-free philosophy of life, or perhaps even your prayer during which you only talked to yourself, after all the despaired weeping and mute groaning about the need of your life, whether you finally could be silent before him and let him speak the word, the word that seemed only to be like a deadly silence to the earlier person who was you. You should feel that you are not falling at all when you give up the frantically violent interior anxiety about yourself and your life. You do not despair at all when you doubt yourself, your wisdom, your strength, your ability to help yourself to life and the freedom of happiness; rather, you are with him suddenly as a miracle that daily has to happen anew and never can become a routine. Suddenly you will experience that the petrifying visage of hopelessness is only God's rising in your soul, that the darkness of the world is nothing but God's radiance which has no shadow, that the apparent waylessness is only the immensity of God who does not need any ways because he is already there.This is the dark grace offered to some Christians who must be thrust into the very depths of their souls, the bottom of their beings, and forced to feel an isolation and aloneness and estrangement that threatens to suffocate the life from them. As your lungs ache and struggle for just one more breath, as you fight with everything you have against the structures that seem to work in concert to silence and destroy you, do not fear. Know that there is no height you can climb, nor depth you can plumb, where God is not with you, listening to you, creating you, and loving you.
Know this and find courage. Would that the pain that often breeds this knowledge be avoided...such is not our cup to drink. As your old illusions of the Church and society are fractured and break apart, as the idol you once bowed before disintegrates, do not fear. Relax into the newly-opened space and listen, really listen, for the voice of the One who has never left you, who has been with you this whole time. Feel the blisters and welts and callouses and know feel these scars as they are redeemed and made able to speak of God's saving power. Find joy in these -- no, grace does not erase memory but it does reconcile us to the past with a joyful hope for the future -- and return to the Church, singing and proclaiming God's saving power. These are the marks of the prophet, the one who has experienced dark grace and emerged, scarred yet redeemed, to proclaim the saving power of God to those in need of Good News.