Jacob pauses at Be'er Sheva on his way to Egypt. He offers sacrifices. He waits. He listens. And the Holy One speaks to him in a night vision.
"He said, I am God, the God of thy father; fear not to go down into Mizraim on account of the servitude I have decreed with Abraham: for a great people will I make thee there" (Genesis 46:3). Targum Pseudo-Jonathan preserves the reason Jacob needed reassurance. He was afraid of the shibbud — the slavery foretold to his grandfather at the Covenant Between the Pieces (Genesis 15:13-14), where God told Abraham that his descendants would be "strangers in a land not theirs" for four hundred years.
Jacob does the arithmetic at Beersheba. If he descends to Egypt with his family, the four-hundred-year clock begins. He does not want to be the one who triggers the slavery. He would rather die in Canaan than be the father of the generation that enters bondage.
The Holy One answers with a paradox that only makes sense in Jewish theology. Fear not to go down. The descent is not the tragedy. The descent is the cradle. "A great people will I make thee there" — in Egypt, in the very place of the decreed slavery, the seventy souls of Jacob's family will grow into a nation.
The sages teach that exile and peoplehood are paired in Judaism. The klal Yisrael, the national body of Israel, is forged in the crucible of Mitzrayim. The same Egypt that enslaves is the Egypt that multiplies. The suffering that Abraham was told about is real, but so is the promise on the other side of it: a great people, a covenant nation, an Exodus.
Jacob listens. He accepts. He rises from the altar and continues the journey. God has just turned his fear into a blessing.