Joseph was using an interpreter to talk to his brothers. So the brothers did not know that Joseph understood their language. But Joseph heard and understood everything they said.
God made this Agreement with Joseph {\cf2\super [467]} \par when God took him out of Egypt.\par In Egypt we heard that language\par we didn’t understand.\par
Moses said to the people, “Remember this day. You were slaves in Egypt. But on this day the Lord used his great power and made you free. You must not eat bread with yeast.
“Remember the month of Abib. [97] At that time, you must celebrate Passover [98] to honor the Lord your God. Why? Because in that month the Lord your God brought you out from Egypt by night.