Meditation is like a single log of wood. Insight and investigation are one end of the log; calm and concentration are the other end. If you lift up the whole log, both sides come up at once. Which is concentration and which is insight? Just this mind.
If you determine your course With force or speed, You miss the way of the dharma. Quietly consider What is right and what is wrong. Receiving all opinions equally, Without haste, wisely, Observe the dharma.
To concentrate is not to meditate, even though that is what most of you do, calling it meditation. And if concentration is not meditation, then what is? Surely, meditation is to understand every thought that comes into being, and not to dwell upon one particular thought; it is to invite all thoughts so that you understand the whole process of thinking.