Joseph has been holding a pose for three chapters. Stern vizier. Egyptian potentate. Accuser, examiner, power. Then he lifts his eyes and sees, standing among his brothers, the boy born of his own mother.
"He lifted up his eyes and saw Benjamin his brother, the son of his mother, and said, Is this your youngest brother of whom you told me?" (Genesis 43:29). The Targum adds the blessing Joseph cannot quite swallow back: "Mercy from the Lord be upon thee, my son!"
Three details break open in that verse. First, the Targum is careful to call Benjamin bar imeh — the son of his mother. Joseph has ten half-brothers in front of him, but only one full brother. Only one who shared Rachel's womb. Rachel died giving birth to this boy (Genesis 35:18), and Joseph has never met him as a grown young man. He is looking at the only living face that holds his mother's.
Second, the blessing itself. Rachamin min kodam Adonai yehei alakh, beri — mercy from the Lord be upon thee, my son. Joseph calls Benjamin my son. He is no more than seven or eight years older than Benjamin, but grief and distance have made him paternal. The Targum hears in his voice the tenderness of a man who has become, in Benjamin's absence, a second father to him from afar.
Third, notice Joseph's restraint. He blesses. He names. Then he flees the room to weep. The vizier who can deny a whole nation of grain cannot deny his own heart one more instant.
Mercy upon thee, my son. That is the line the Targum preserves. It is the sound of a wound opening toward healing.