What does Genesis 44:28 mean?

These are the words of Jacob, speaking to nine of his oldest sons. They returned from Egypt, with one brother held as security, with a command to bring their youngest brother, Benjamin (Genesis 42:19–20). Judah is explaining this conversation to the Egyptian ruler who made that demand. He is pleading for leniency, so that Jacob is not deprived of yet another son (Genesis 44:18–27). Judah does not realize that the ruler is Joseph, the brother the oldest ten sold as a slave twenty years ago (Genesis 42:21–23).

Even though he is testing his brothers, Joseph must have been deeply moved by Judah's account. This was very likely the first time he heard what had happened at home after he had been carried away by the slave traders (Genesis 37:24–28).

Jacob had described Joseph as one of two sons born to him by his wife (Genesis 35:24). One of them had "left him," Jacob had said, after being "torn to pieces" by a wild animal (Genesis 37:31–34). Then, with heartbreak, "I have never seen him since." Joseph learned at last how deeply his father had mourned him. Painfully, he also learned his father had assumed him to be dead for the last two decades.