In her novel, "Briefing for a Descent into Hell," Dorris Lessing makes the point that perception is largely dependent on what we expect to perceive. A character in her novel observes that whole armies of angels could fly past a person, but if that person were not expecting such a phenomenon, it would likely go unnoticed.

The Torah commentators make this same point by asking why the Bible, in introducing us to Abraham, is seemingly silent about his virtues. Why aren't we told what made Abraham worthy to have a close relationship with the Almighty?

The answer is that the Torah is actually telling us about Abraham's greatness just by the mere fact that Abraham heard the Almighty's call. While God talks to many, only Abraham was able to perceive His words.

One of the most remarkable "perceptions" of all-time appears in this week's Torah portion, Shmot. In the Parsha, Moses is shepherding his father-in-law's sheep in the middle of the desert. Suddenly, Moses spots an extraordinary phenomenon: a bush is burning, yet is not consumed. Curious to know what is going on, he turns towards the Bush and ... suddenly a voice is heard. God speaks to Moses and charges him with the responsibility of saving the Jewish people from slavery in Egypt.

There is much discussion amongst the Torah commentators as to why the Almighty would choose the vision of a Burning Bush to initiate His contact with Moses.

Rashi sees the Burning Bush as a symbol of God's sheltering presence during times when the Jews will go through "burning difficulties." Just as the Bush is sustained because the Almighty supports its existence, so too will the Almighty support the Jewish people's survival in their time of need.

Rabbenu Bechaya offers two additional interpretations. He quotes a Midrash that notes the Hebrew word for bush ("Sneh") is similar in spelling to the Hebrew word "Sinai." This Midrash sees the Burning Bush, then, as a symbol of the fire which will burn atop Mount Sinai during the giving of the Ten Commandments.

On another level, Rabbenu Bechaya suggests that the image of the Burning Bush is a paradigm for all physical reality. Since the physical world is a product of Godly, spiritual creation, it is logical to assume that the physical universe should be consumed by the overwhelmingly powerful spiritual flow emanating from God. The continued existence of the entire physical universe, therefore, is very much like the continued existence of this Burning Bush. Through the symbolism of the Bush, the Almighty gave His reassurance to sustain the world.

* * *

Perhaps the most striking observation is made by the Sforno. He says that at the Bush, Moses was receiving a lesser level of prophecy than he would receive in later years. Jewish thought maintains that there was a crucial, substantive difference between Moses' and all other prophets' prophecies. While all other prophets received God's messages in the form of images that had to be subsequently interpreted, Moses heard God's word directly without the need for intermediary images. The Burning Bush, however, is the one exception to this rule, and suggests that Moses' spiritual perceptions still were in need of development.

The Tosafot Daa't Zekanim also note that a bush cannot be used for idol worship and thus Moses was hearing God's will from a medium that would be free of all spiritual pollution.

Other Midrashim see the Bush as a sign of humility, signaling to Moses that God dwells with the truly humble. Just as the Burning Bush is a symbol of lowliness, but pregnant with possibilities beyond the natural order, so too would Moses' later prophecies go beyond what he could spiritually perceive at the present moment ... taking him to heights that no other human would ever achieve in history.