The following comes from the Beginning to Pray site:
Is contemplation an uninteresting wilderness? Many religious who have dedicated their whole lives to prayer can speak like this, including authors like Thomas Merton. These kinds of expressions suggest those purgative experiences in prayer where our conversation with God takes on a kind of monotonous tone. It is like that part of an adventure where nothing seems to be happening and everything looks the same.
Those who suffer this find themselves wandering, searching through a forest of unanswerable questions: Is He asleep? Why isn't something happening when I pray? Sometimes prayer can seem boring and can even feel like a complete waste of time. This can be dissatisfying and even discouraging. Yet this is a part of the journey of prayer and, as a character in a Tolkien story observes, not all who wander are lost. In this real adventure, each step potentially unleashes into the world the transforming power of Divine Mercy if we allow ourselves to be guided by love.
Prayer can be extremely difficult when we do not understand or have real feeling about what God is doing. And, sometimes, the Lord can choose to keep us in the dark about his mysterious purposes for a very long time. Only after we have grown accustomed to the vast expanses of unfamiliar horizons does the apparent lack of consolation begin to disclose its beauty to us.
We sometimes glimpse, if only for a rare and transitory moment, a greater interior freedom, a real humility, a deeper strength, and a firmer sense of purpose. A bold desire to glorify God with an unflinching resolve has taken hold. In our dryness, we know these movements of holiness in our heart did not come from ourselves - they are the fruit of Someone else's life born in us.
St. John of the Cross was so at home with this prayer, he came to see it as a sheer grace, a providential moment of pure luck. This is because abiding with God is our true home, the end of the journey we have undertaken. But He is "so totally other" than that with which we are comfortable, to find Him, He must lead us beyond what is comfortable and into a truly tedious vulnerability. It is as uninteresting as death on a Friday afternoon. Yet it is through this wilderness that we must pass if we are to live life to the full -- if we are to know the joy of possessing the One who longs to possess us in love.