Do not give up then, but work away at it till you have this longing. When you first begin, you find only darkness, and as it were a cloud of unknowing. You don’t know what this means except that in your will you feel a simple steadfast reaching out towards God. Do what you will, this darkness and this cloud remain between you and God, and stop you both from seeing God in the clear light of rational understanding, and from experiencing his loving sweetness in your affection. Reconcile yourself to wait in this darkness as long as is necessary, but still go on longing after the One whom you love. For if you are to feel the Presence and see God in this life, it must always be in this cloud, in this darkness.
The Cloud of Unknowing (14th century, author unknown)