Genesis 44:22

And we said unto my lord, The lad cannot leave his father: for if he should leave his father, his father would die.

Benjamin had stayed at home with Jacob while his other brothers had gone to Egypt for grain, and the reluctance to bring him away was fear of adding sorrow to their father. Jacob regarded Benjamin as his only remaining son, all that was left of the mother he loved, having grieved greatly over the loss of Joseph. His life was bound up with Benjamin's in such deep attachment that separation from the lad would bring him to grief and death.

The words are Judah's statement, made with his brothers in a private plea to Joseph, that the lad cannot leave his father. Judah had pledged himself as surety for Benjamin, to bear the blame forever if he did not bring him back to his father. He used this danger to his father's life to explain Jacob's reluctance to let Benjamin go to Egypt and to plead for Benjamin's release. Because he could not face his father without Benjamin with him and feared returning without him, he nobly offered to remain as a bondman in his brother's place and let Benjamin go up with his brethren.