Numbers 33:4
For the Egyptians buried all their firstborn, which the LORD had smitten among them: upon their gods also the LORD executed judgments. For the Egyptians buried all their firstborn, which the LORD had smitten among them: upon their gods also the LORD executed judgments.
The plagues upon Pharaoh and the Egyptians were particularly adapted to that people and in every instance had strict reference to their idolatry. Upon their gods also the Lord executed judgments at the same time He smote the firstborn, executing judgment against all the gods of Egypt and exposing those gods as powerless. The Nile, consecrated as the chief national god and regarded as the giver of all their gods, was turned to polluted blood with the stench of dead fish. The frog, held as an object of both reverence and abhorrence, was sent upon the Egyptians in judgment.
A plague struck at priestly purity until even the magicians acknowledged that it was the action of God. God, being long-suffering, slow to anger, and full of compassion, gave each judgment time to do its work. In this way the Egyptians were brought to curse the very objects they had worshiped. All who were willing had evidence of His power by which they might submit and escape His judgments.