R. Zera says: Moses certainly knew and David, too, knew [the exact time of midnight]. Since David knew, why did he need the harp? That he might wake from his sleep. Since Moses knew, why did he say ‘about midnight‘? — Moses thought that the astrologers of Pharoah might make a mistake, and then they would say that Moses was a liar. For so a Master said: Let thy tongue acquire the habit of saying, ‘I know not’, lest thou be led to falsehoods [lying]. R. Ashi says: It was at midnight of the night of the thirteenth passing into the fourteenth [of Nissan], and thus said Moses to Israel: The Holy One, blessed be He, said: Tomorrow [at the hour] like the midnight of tonight, I will go out into the midst of Egypt.
The Gemarrah questions Moses’ use of an equivocal term instead of an exact statement about the time when God will go out into the midst of Egypt during the Passover. One interpretation is that Moses wanted to avoid the semblance of lying so as not to give the Pharaoh’s Astrologers the opportunity to say that Moses was lying. We are now presented with an important injunction to avoid spreading falsehoods. This is important for a number of reasons. However, we must first ask why Moses was so concerned about Pharaoh’s astrologers. Moses knew that Egypt was an idolatrous society that saw fate as a confluence of natural forces. Events occurred in accordance to the natural order ruled over by the stars. Moses knew that there would be at least two problems that would be encountered when the astrologers heard of Moses’ prophecy. First, the astrologers might make a mistake in their calculation of time. Then, if Moses’ prophecy came true too early or too late according to their calculation, the astrologers could say that Moses lied to confuse the Egyptians. However, there is another issue that is implied, but not specifically addressed in this paragraph. Why are we talking about Pharaoh’s astrologers? As we mentioned before, Egyptian astrology assumed that natural events occurred because the forces of nature, as indicated by the stars, created them. If Moses prophesized that HaShem would act exactly at midnight, the astrologers could say that this was due to a natural confluence of circumstances, not through divine will. It is precisely because Moses wanted to indicate that a divine intervention would occur that he did not use precise language to designate when the event would occur. HaShem, having Divine Will, was not required to act according to the dictates of natural cycles. And so, in order to account for HaShem’s will, Moses needed to use an equivocal term.
So then, why is the point made that: ” R. Zera says: Moses certainly knew and David, too, knew [the exact time of midnight]. Since David knew, why did he need the harp? That he might wake from his sleep.” There are two types of sleep indicated here. First is the sleep of the lack of awareness of God’s will in the world. Second is David’s physiological sleep. As we pointed out before, the harp couldn’t possibly be a mundane musical instrument. Rather, the harp seems to be a metaphorical indication of sleep phenomena. David remained sufficiently conscious to rouse himself when he encountered the harp in his sleep.