Source: www.hinduismtoday.com
The mind is like milk. If you keep the mind in the world, which is like water, then the milk and water will get mixed. That is why people keep milk in a quiet place and let it set into curd, and then churn butter from it. Then that butter can easily be kept in the water. The mind will float detached on the water of the world.
Sri Ramakrishna Paramhansa