The quote is by Pastor and theologian Paul Tillich. It is from his book Shaking the Foundations and it reads like this:
Do we know what it means to be struck by grace? It does not mean that we suddenly believe that God exists, or that Jesus is the Savior, or that the Bible contains the truth. To believe that something is, is almost contrary to the meaning of grace. Furthermore, grace does not mean simply that we are making progress in our moral self-control, in our fight against special faults, and in our relationships to men and to society. Moral progress may be a fruit of grace; but it is not grace itself, and it can even prevent us from receiving grace. For there is too often a graceless acceptance of Christian doctrines and a graceless battle against the structures of evil in our personalities. Such a graceless relation to God may lead us by necessity either to arrogance or to despair. It would be better to refuse God and the Christ and the Bible than to accept them without grace. For if we accept without grace, we do so in the state of separation, and can only succeed in deepening the separation. We cannot transform our lives, unless we allow them to be transformed by that stroke of grace. It happens; or it does not happen. And certainly it does not happen if we try to force it upon ourselves, just as it shall not happen so long as we think, in our self-complacency, that we have no need of it. Grace strikes us when we are in great pain and restlessness. It strikes us when we walk through the dark valley of a meaningless and empty life. It strikes us when we feel that our separation is deeper than usual, because we have violated another life, a life which we loved, or from which we were estranged. It strikes us when our disgust for our own being, our indifference, our weakness, our hostility, and our lack of direction and composure have become intolerable to us. It strikes us when, year after year, the longed-for perfection of life does not appear, when the old compulsions reign within us as they have for decades, when despair destroys all joy and courage. Sometimes at that moment a wave of light breaks into our darkness, and it is as though a voice were saying: “You are accepted. You are accepted, accepted by that which is greater than you, and the name of which you do not know. Do not ask for the name now; perhaps you will find it later. Do not try to do anything now; perhaps later you will do much. Do not seek for anything; do not perform anything; do not intend anything. Simply accept the fact that you are accepted!” If that happens to us, we experience grace. After such an experience we may not be better than before, and we may not believe more than before. But everything is transformed. In that moment, grace conquers sin, and reconciliation bridges the gulf of estrangement. And nothing is demanded of this experience, no religious or moral or intellectual presupposition, nothing but acceptance.
There you have it. I hope you enjoyed it as much as I did!