The world is insane. It tries to get rid of its insanity by the use of wisdom and reason; and it looks for many ways and means, for all sorts of help and advice on how to escape this distress. But the shortest and surest way is to go into a little room (Matt. 6:6) or a corner and there to open your heart and to pour it out before God, filled with complaints and sighs, but also with confidence and trust that as your faithful heavenly Father He wants to give you His help and advice in this distress.
Martin Luther, Commentary on the Sermon on the Mount, 231-232 quoted by Scot McKnight, Sermon on the Mount (The Story of God Bible Commentary).