When we read about the 10 plagues everything is repeated twice: once when Hashem commands Moshe and a second time when Moshe executes the plague. The Torah could simply write "and he did so" after ...
Possible Duplicate: “Moshe cried out” - really? For this plague, the posuk says Moshe left and "cried out" (tzoak) to God that the plague should stop. Why did this plague affect ...