Come to me, all you who are weary and burdened, and I will give you rest. Matthew 11:28 (NIV)
A speaker was talking about managing difficult situations. He raised a glass of water and asked the audience about the weight of the contents in the glass. The answers varied from 20 to 500 grams. The presenter told them that the absolute weight did not matter too much. The important thing was the length of time he could hold the glass.