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.
Ajahn ChahOne day some people came to the master and asked: How can you be happy in a world of such impermanence, where you cannot protect your loved ones from harm, illness or death? The master held up a glass and said: Someone gave me this glass; It holds my water admirably and it glistens in the sunlight. I touch it and it rings! One day the wind may blow it off the shelf, or my elbow may knock it from the table. I know this glass is already broken, so I enjoy it - incredibly.
Ajahn Chah