it came to pass. Compare 2Ki 37:36.
that night: i.e. the night of the prophecy when the promise was fulfilled. Compare "that day" (Luke 21:34; 1 Thessalonians 5:4).
the Angel of the LORD: i.e. the destroying Angel. Compare 2 Samuel 24:16.
they: i.e. the king and his people.
dead corpses. Figure of speech Pleonasm, for emphasis.