Throughout the Tanach we find people or groups of people who presume that they can know, with both precision and certainty, when certain future events which have been prophecied will occur, and just as we find with Achashverosh in today’s daf (Megillah 11b), they each make the claim: אנא חשיבנא ולא טעינא – ‘I shall make a calculation [about when a particular prophecy will occur] and I will not err’.
Yet in almost every instance, as recorded both in today’s daf and elsewhere in the Midrash and Gemara they err, and in almost every case it becomes evidently clear that the predicted timeline of any future event or prophecy can only be understood retroactively.
Clearly, a very simple lesson that we can draw from here is that our insistence that we can know, in real time, if, how and when prophecies will be realised is foolish.
In terms of prophecies about what may happen in the future, it is important to remember the words of Rabbi Sacks that, ‘a prophet is not an oracle; a prophecy is not a prediction. Precisely because Judaism believes in free will, the human future can never be unfailingly predicted. People are capable of change. God forgives. As we say in our prayers on the High Holy Days: “Prayer, penitence, and charity avert the evil decree.” There is no decree that cannot be revoked. A prophet does not foretell. He warns. A prophet does not speak to predict future catastrophe but rather to avert it. If a prediction comes true it has succeeded. If a prophecy comes truth it has failed’ (Covenant and Conversation: Deuteronomy pp. 160-161).
But even in terms of prophecies that reference specific spans of time – such as the 40 days when Moshe was on Mount Sinai (which, as our Sages note, the people miscalculated), or the 70 years of the Babylonian exile (which, as discussed in today’s daf, was also miscalculated by Achashverosh and others) – we see from our daf and numerous other biblical and rabbinic sources that we can only know when the start of the count of a specific period of time began once it has ended.
So why do we keep on repeating the same mistake of claiming אנא חשיבנא ולא טעינא – ‘I shall make a calculation and I will not err’? I believe that it is because we think that God operates according to the tick of our clock, whereas what we don’t realise is that even when God communicates via prophecy that certain events will occur after a specific span of time, they occur based on the tick of God’s clock – and just as God says וראית את אחרי ופני לא יראו – ‘you will see My back, but My face may not be seen’ (Shemot 33:23), so too, the predicted timeline of any future event or prophecy can never be known with certainty ahead of time, but only afterwards, from the ‘back’.