"Libra also rules the kidneys, the organs of elimination that maintain the chemical balance of the body. Through the elimination of the poisonous toxins in our lives, we ensure a balanced life. The scales represent balance. There are seven straight lines of equal length in the scales, representing the seven centers in the body, and the seven original planets - Mercury, Moon, Venus, Jupiter, Mars, Sun, and Saturn."
http://globalpsychics.com/enlightening-you/numerology/repeating-numbers.shtml