Prophesying at the time of the return to Zion after the exile to Babylonia, the prophet mentioned the four fasts that had been observed there and said they would be abolished – and more than that, would become holidays, times of celebration. We are now in the fourth month. According to Jeremiah 52:6, on the ninth day of this month, Tamuz, there was no food left in Jerusalem. The fast that we have in the fourth month, however, is on the 17th, because that was the day the Romans breached the walls of Jerusalem in the year 70 CE (Ta’anit 4:6).It seems likely that after the first return to Zion, those four mourning days were no longer observed. When the State of Israel came into being, there were those in the religious Zionist world who said the time had come to abolish these fasts again – if not Tisha Be’av, at least the other three, which are observed only during the daytime. Observed or not, there is little question that for those who see in the establishment of the state an act of redemption, the feeling of mourning that once reigned during the Three Weeks has diminished – and rightly so. Nevertheless, there is some value in remembering the events commemorated by these three weeks.Aside from the fact that it is important to be aware of our history, the commemoration of the two major acts of destruction – the first by the Babylonians in 586 BCE and the second by the Romans in 70 CE – serves to remind us that in both instances, these catastrophes could have been avoided. They were not ordained, and they were not inevitable.Our prayers use the phrase, “Because of our sins we were exiled from our land.” “Our sins” can be explained in two different ways.One is that we did not deserve to continue living in our land because we violated the basic laws of the Torah – laws of morality and decency, as well as of fidelity to the Lord. That is what the prophet Jeremiah taught prior to the destruction. That is also what the Sages taught when they said the Second Temple was destroyed because of such sins as baseless hatred.But Jeremiah also discerned another “sin,” and that was the mistaken attempt to play international politics by siding with the Egyptians against the Babylonians: “What, then, is the good of your going to Egypt to drink the waters of the Nile?” (Jer. 2:23; see also Jer. 37:6) And later, when the catastrophe was upon them, he said they should accept the yoke of Babylon and not make things worse (Jer. 27:12). No one listened.Similarly Rabbi Yohanan Ben Zakkai counseled the people not to rebel against Rome, the mightiest power in the world at that time. “My children,” he said to the zealots, “why do you destroy this city, and why do you seek to burn the Temple? For what is it that he [the Emperor Vespasian] asks of you? Verily he asks naught of you save one bow or one arrow, and he will go off from you.” They, too, would not listen, and vowed to go to war (Avot D’Rebbi Natan A 4). The result was catastrophic.The inability to read the reality, to refrain from extreme actions and come to terms with the situation in order to prevent death and destruction, was the underlying cause of these tragedies. It is all very well to be courageous, but it is also good to be prudent. As King Solomon taught, “There is a time for every experience under heaven... a time for war and a time for peace” (Ecclesiastes 3:1,8). One has to know when the time is right for each course of action and discern the difference.Of course, it is impossible to second-guess history, but it seems possible that had the leadership heeded Jeremiah and had the zealots listened to Rabbi Yohanan, these catastrophes could have been averted – and who knows what this would have meant for the history of Judaism and the world? For that, we should indeed mourn.The writer, former president of the International Rabbinical Assembly, was the founding director of the Schechter Rabbinical School. His latest book is Entering Torah.