وَإِذْ فَرَقْنَا بِكُمُ الْبَحْرَ فَأَنجَيْنَاكُمْ وَأَغْرَقْنَا آلَ فِرْعَوْنَ وَأَنتُمْ تَنظُرُونَ
Wa iz faraqnaa bikumul bahra fa anjaynaakum wa aghraqnaa aala Fir'awna wa antum tanzuroon
And remember when we parted the sea for you and saved you, and drowned Pharaoh's people while you looked on.
Faraqnā, the verb for parting the sea, comes from the root that separates one thing from another. Three verses later the same root names what is given to Musa, the furqān, the criterion that separates truth from falsehood. The sequence puts a physical division and a moral one under one word, and the escape happens while those escaping are watching rather than acting.