Yosef leveled an excoriating accusation at his brothers, denouncing them as treacherous spies. As Ramban explains, they responded that they were all sons of one man, who was an individual of eminent standing and whose reputation was well-known. It would not be difficult for Yosef to inquire about him and his family. In other words, they were contending that since they were distinguished people and sons of a well-known, eminent person, labeling them as spies was totally out of line. Ramban adds that they were all sent together, because their father did not want to break up the family unit. In fact, Yaakov Avinu could just as well have sent one or two of his sons with a group of slaves to accompany them. Why did he insist on sending his whole family just to purchase some food? In addition, what about the bitul Torah, wasting time from Torah study, which is inevitable when one is on the road? The mitzvah of yishuv Eretz Yisrael, inhabiting the Holy Land, should not be ignored either. Traveling to Egypt in those days was not a hop, skip and jump. It was a journey. Did they all have to go?
Horav Henach Leibowitz, zl, derives from here that Yaakov Avinu viewed the achdus, unity, of his family as superseding the mitzvos of Torah study and yishuv Eretz Yisrael – despite the apparent danger. Yaakov did not want his sons to separate from one another – even for a short while. By remaining together as a family, their love for one another would be complete. This is what the brothers emphasized to Yosef. Our family is unique. We stay together, because that way we remain together. Yaakov was even willing to chance danger – both spiritual and physical – so as not to break up the family unit. He understood that true success in Torah study and mitzvah observance is predicated upon the foundation of achdus Yisrael.
The Rosh Yeshivah notes that some truly believe that they fulfill the mitzvah of ahavas Yisrael, love of Israel, when in fact they are far from fulfilling this mitzvah. They expound the importance of achdus, unity, but do not understand its true meaning. Do they love each and every Jew individually, as well as the unit collectively as a whole? No! They only really care about Am Yisrael – the nation – the entire unified nation. However, the mitzvos of Jewish unity and love for Klal Yisrael begin with our love for every single Jew – regardless of religious background, affiliation, personality, etc. If he is a Jew, then we already have a reason to care for him. He is one with us. We are all in this together.