Seeing the Sounds

The Baal Shem Tov told of a deaf man who entered a hall where everyone danced to joyful music. He thought they were mad, because he heard no music. A wise person would have understood that they were dancing to a melody and would have joined in. The Degel uses this to explain the verse that the people saw the sounds at Har Sinai. Some could not fully hear the Torah, but they saw the malochim dancing and understood the delight, and they too came to appreciate the sweetness of the Torah and joined.