وَتَجَلَّى لَكَ الْعِبَرُ فَتَعَامَيْتَ
Lessons became clear before you, yet you acted as if blind.
Tajallā means to become manifest. Al-ʿibar is the plural of ʿibrah, an instructive lesson drawn from events. Taʿāmayta means to act blind or deliberately avoid seeing.
The point is not physical blindness. It is the failure to learn even when the significance of events has been made plain.