On the festival of Lag B'Omer there is a custom to shoot arrows from a bow and arrow. Lag B'Omer is the day of the passing of Rabbi Shimon Bar Yochai. The day on which he left this world, Rabbi Shimon revealed many of the hidden secrets of the Torah, the hidden light. The revelation of the hidden light is like the revelation of the colors in the rainbow. A rainbow reveals the anatomy of white light.
White light seems indivisible.
No detail can be discerned in its pure whiteness. The rainbow reveals the secret of the white light. It shows us how the white light is really composed of all the colors. Just as the coming of Mashiach is compared to the revelation of the hidden light, so too Chanukah, the Festival of Lights, is a symbol of the revelation of the hidden light, the hidden Torah. Of all Yaakov Avinu's sons, the one most closely associated with Torah study is Yissaschar.