"And from among his brothers he took [five men]" (Genesis 47:2). And why does it say "and from among his brothers he took"? To teach you that all of the tribes were mighty men. And who were these five? Reuben, Simeon, Levi, Issachar, and Benjamin. And why did Joseph the Righteous take these five men from among his brothers? Because he knew who among his brothers was mighty and who was weak. And he said: If I present the mighty ones among them before Pharaoh, perhaps he will make them into his men of war. Therefore he presented these five men who were not mighty.
Why Joseph Chose His Five Weakest Brothers Before Pharaoh
Midrash Aggadah, Genesis 47:2
ומקצה אחיו לקח. ומפני מה אמר ומקצה אחיו לקח, ללמדך שכל השבטים גבורים היו, ומי היו אלו החמשה, ראובן שמעון לוי יששכר ובנימן, ומפני מה לקח יוסף הצדיק חמשה אנשים הללו מאחיו, לפי שהיה מכיר מי גבור באחיו ומי חלש, ואמר אם [אני] מעמיד גבורים שבהם לפני פרעה, שמא יעשה אותם אנשי מלחמתו, לפיכך העמיד אותם חמשה אנשים שלא היו גבורים: