What is true beauty?
Most often, when the Torah mentions a beautiful person, it is referring to a person whose outer appearance reflects their inner soul. For example, we are taught about the beauty of our matriarch Sarah. According to our tradition, other women looked like monkeys compared to Sarah. The Talmud says that Sarah was as beautiful at the age of 20 as a seven-year-old child. Yet isn't 20 closer to the ideal age of beauty than seven? What is it about a child that is more beautiful than a young woman?
The explanation is simple. The beauty of children is the beauty of purity of spirit; they act the way they feel without being influenced by insincerity. There are no put-ons or pretending. As Rabbi Hirsch states, the secret of beauty does not lie in superficial cosmetics, but can be acquired only from within.... Only a beautiful, pure spirit, inspired by the spirit of God, can produce a physical image of angelic beauty. Sarah's beauty was one of complete synchronization between external and internal, between body and soul. This kind of beauty does not fade with age, pregnancy, or weight gain. It is a beauty that is cultivated inwardly and shines forth.
Judaism teaches that we all have precious souls and that externals should reflect this inner beauty. For example, both men and women are encouraged to maintain an attractive, dignified appearance. Jewish law forbids a Torah scholar to wear ripped or stained clothing. Our priests, the kohanim, could not perform the service in the Holy Temple in Jerusalem without the appropriate attire. We are not to become gluttonous or mistreat our bodies by overindulgence or self-mutilation. In essence, our bodies should be treated and dressed with respect, since they house what is most precious and beautiful, our souls.
I was once asked a very disturbing question while teaching about this concept. A student said to me, "Why should I dress like I'm dignified if I feel worthless inside?" The answer is that G-d created every person in the Divine image. We all have the beauty of this Divine image -- the soul -- inside us. Our external appearance should reflect its internal presence even if we don't always feel it.
This is true in mitzvot as well. We are supposed to beautify the mitzvot. Most traditional homes have beautiful silver candlesticks for lighting Shabbat candles and a silver kiddush cup to hold the wine over which we make a blessing on Shabbat. The Torah scroll itself is encased in fine cloth and laden with gold, silver, and precious jewels. The idea is that the mitzvah itself is spiritually beautiful and should be reflected that way in the physical world as well, in the same way that the body should reflect the beauty it holds. (by Chana Kalsmith)