The Sage Chiya bar Rav shot an arrow while examining a case of annulling a vow. This seemingly bizarre behavior of a sage in the process of dealing with someone's vow is explained by the commentaries in two entirely different ways. They diverge on the issue of Chiya's position regarding the length of time the Torah allots a husband to cancel his wife's vow.

In our mishna we are told that on the day that a man hears of his wife's vow he has only until the nightfall to cancel her vow, regardless of what time during the night or day he became aware of it. Other sages quoted in the gemara contend that he has a full 24-hour period from the time he heard the vow.

Ran's version of the text is that Chiya went along with the majority view that he has only till the end of the day. The account of his shooting an arrow was, therefore, not related to the issue of husband cancellation. It was rather intended to teach us about his position regarding a sage's annulment of vows. While other opinions limited that power to a situation in which the sage could find an "opening" for the vow-maker to express his regret (i.e., that had he been aware of a certain consideration he would not have made such a vow), it was Chiya's opinion that the sage need not bother to find such an opening and could annul the vow based only on the regret expressed at having made the vow. Since this required no real effort on his part he was able to handle this annulment even while being preoccupied with his archery.

Rosh, however, has a different text that indicates that Chiya's position was that a husband had a full 24 hours in which to cancel his wife's vows. When Chiya heard his wife make a vow he did not immediately cancel it because he wished to discourage such future behavior by keeping her in suspense that her vow might indeed be binding. He therefore placed an arrow in the wall to mark the exact spot of sun and shade when the vow was made. He could then cancel his wife's vow the next day just before the 24-hour period was up.

Nedarim 76b

"Who is the wise man that may understand this," asks the Prophet Yirmiyahu (9:11-12), "and who is the one to whom Hashem has spoken that he may declare it -- why has the land been lost?"

The answer is supplied by Hashem: "Because they have forsaken My Torah which I gave them and have not obeyed My voice."

Rabbi Yehuda quoted the Sage Rav as calling attention to the fact that no one could find the reason for Jews being exiled from their land, until Hashem revealed the reason. This question, he notes, was asked of the sages, the prophets and the angels, and no one could offer an explanation. This indicates that there was some subtle sin not discernible to anyone but Hashem.

And what is the meaning of Hashem's explanation? asks Rav. What is the difference between "they have forsaken My Torah" and "have not obeyed My voice?"

Rabbeinu Yona, quoted by Ran, explains that Rav deduced that the cause for exile could not possibly be that Jews literally abandoned the study of Torah, for had this been so it would not have eluded the sages, prophets and angels. His conclusion is, therefore, that Jews did in fact study Torah, and as long as they had this merit of Torah study Hashem did not yet punish them for their other sins. This is why no one was able to find a reason for the removal of Divine protection that brought about destruction and exile. Only Hashem knew the answer:

Only Hashem, who knows the innermost thoughts of man, was aware that Jews had approached the study of Torah as if it were just another form of wisdom, and had not considered it important enough to offer a blessing to Hashem for this opportunity. Since they did not approach their Torah study with the proper reverence and dedication, it was not capable of providing them with protection form punishment for their other grave sins which caused them to lose their land.

Nedarim 81a