In Jewish tradition all important events are marked with a blessing recited over a cup of wine. For Friday night Kiddush, a wedding or a Bris, a cup is filled to the top and the blessing is recited. In some communities the custom is not just to fill the cup but to make sure that the wine spills over and the cup overflows. This particular custom actually represents an idea that is at the core of personal growth.
The sages teach that "when wine enters the secrets come out". Alcohol removes inhibition and causes the individual to reveal that which would otherwise be private. This can be embarrassing and dangerous, but there is a very positive side to it as well. In the spiritual sense, this phenomenon is a symbol of intense inspiration and happiness that allows us to access the infinite hidden power of the soul, encouraging us to grow and rise above our perceived limitations.
That is why we let the cup overflow. The wine that spills over is a sign that we are not satisfied to remain within the confines of our normal routine. The joy represented by the wine allows us to spill over and break out of ourselves, exploring new heights of spiritual and personal achievement.
But here lies a deep secret. Apart from a required minimum measurement, the size of the cup is irrelevant. What matters is that it should be full and overflowing. We each have our own size cup. Some are large and others are small. We are not all hugely talented, deeply spiritual or amazingly bright. But we all do possess the ability is to ensure that our cup spills over - we all can grow just a little bit more than we are comfortable with.
The cup of wine is referred to as kos shel beracha - a cup of blessing. Bigger blessing doesn't come from a bigger cup. Blessing comes from a full and overflowing cup. Assess what the size of your cup is and make sure it spills over.