When I heard this for the first time, it made my mind click again. Shunryu Suzuki spoke about this in detail - but here's my take.
We suffer because we see things as separate from ourselves. You probably think you were born, you live and then you die. Ha!
Imagine if you will a waterfall. Before the waterfall, water particles merge together to become one steady stream. During the waterfall, water particles break into individual drops. After the waterfall, water particles re-unite to become one steady stream.
We are the water and we take on different forms. For the short amount of time when we become water droplets, we suffer because we are separate from one another. We see ourselves as separate so we struggle with it. But the natural order of things brings us together, and everything becomes one again and again.
