Yaakov sends his sons to Egypt to purchase grain, and upon their return he hears of the trouble they encountered there. Specifically, the Egyptian viceroy imprisoned Shimon and demanded that the brothers bring him their youngest brother, Binyamin. Yaakov, however, outright refuses to allow Binyamin to go. As the famine conditions in Canaan intensify, Yaakov asks his sons once again to buy grain in Egypt, but they then remind him of the viceroy's strict orders not to return to Egypt without Binyamin. At this moment of frustration, Yaakov asks his sons, "Why have you wronged me, by telling the man that you have another brother?" (43:6).
On this verse the Midrash (Bereishit Rabba 91) comments, "Yaakov Avinu never said anything pointless ['davar shel batala'] except here. The Almighty said, 'I am busy making his son a ruler in Egypt - and he says, why have you wronged me?!'"
The power of this passage relates to the simple but critical message it conveys, and the everyday relevance of that lesson. Nothing constructive is served by this question Yaakov poses to his sons. The reason why they divulged their family information is of no use now, when they face the threat of starvation so long as Binyamin does not accompany them to Egypt. The Midrash therefore considers this question a "davar shel batala," a pointless remark on Yaakov's part. The great patriarch never uttered a non-constructive remark in his life, until now.
On one level, this teaches an important lesson in interpersonal relationships. When mistakes or oversights occur, one can only exacerbate the resulting difficult situation by asking the responsible party after the fact, "Why did you do that?" Nothing positive results from such questioning. The best - and only - way to deal with errors is to look ahead, pick up the pieces, and leave the mistakes of the past for memory.
The Midrash, however, points to a more inherently theological problem with non-constructive questioning of this sort. At times of crisis, the question of "why" is not only of less value than that of "what to do now," but also far less appropriate. As believers in an omniscient, all-powerful God infinitely greater than any of us, we firmly trust that everything in the world serves a purpose, one which, more often than not, eludes our comprehension. God does not ask us to decipher His master plan or identify the rationale behind the manner in which He conducts the world. Instead, He demands that we work to improve that world, under whatever conditions we happen to find it. The Midrash therefore criticizes Yaakov's question to his sons. Why things turned out the way they did should not interest him; he must rather conceon how to handle the difficult situation he now confronts.