He cast upon them the fierceness of his anger ... - This verse is designed to describe the last, and the most dreadful of the plagues that came upon the Egyptians, the slaying of their first-born; and hence, there is such an accumulation of expressions: anger - fierce anger - wrath - indignation - trouble. All these expressions are designed to be emphatic; all these things were combined when the first-born were slain. There was no form of affliction that could surpass this; and in this trial all the expressions of the divine displeasure seemed to be exhausted. It was meant that this should be the last of the plagues; it was meant that the nation should be humbled, and should be made willing that the people of Israel should go.
By sending evil angels among them - There is reference here undoubtedly to the slaying of the first-born in Egypt. Exodus 11:4-5; Exodus 12:29-30. This work is ascribed to the agency of a destroyer (Exodus 12:23; compare Hebrews 11:28), and the allusion seems to be to a destroying angel, or to an angel employed and commissioned to accomplish such a work. Compare 2 Samuel 24:16; 2 Kings 19:35. The idea here is not that the angel himself was evil or wicked, but that he was the messenger of evil or calamity; he was the instrument by which these afflictions were brought upon them.