The locusts came upon them, "because," God said, "the locusts, which are My great army, shall take vengeance upon the Egyptians for having desired to destroy the nation that is called My hosts." "Darkness," said God, "which is divided from the light, shall come and take vengeance upon the Egyptians for desiring to destroy the nation upon which shineth the light of the Lord, while gross darkness covers the other peoples." The tenth plague, the slaying of the first-born, God inflicted, saying, "I will take vengeance upon the Egyptians for having desired to destroy the nation that is My first- born. As the night divided itself for Abraham, that his enemies might be vanquished, so I will pass through Egypt in the middle of the night, and as Abraham was proved by ten temptations, so I will send ten plagues upon Egypt, the enemy of his children."[173] THE PLAGUES BROUGHT THROUGH AARON From the infliction of the first of the plagues until the passing of the last, after which the Egyptians yielded all that Moses and Aaron demanded, there elapsed a whole year, for twelve months is the term set by God for the expiation of sins. The deluge lasted one year; Job suffered one year; sinners must endure hell tortures for one year, and the judgment upon Gog at the end of time will be executed for the length of one year.[174] Moses announced the first plague to Pharaoh one morning when the king was walking by the river's brink. This morning walk enabled him to practice a deception. He called himself a god, and pretended that he felt no human needs. To keep up the illusion, he would repair to the edge of the river every morning, and ease nature there while alone and unobserved. At such a time it was that Moses appeared before him, and called out to him, "Is there a god that hath human needs?" "Verily, I am no god," replied Pharaoh, "I only pretend to be one before the Egyptians, who are such idiots, one should consider them asses rather than human beings."[175] Then Moses made known to him that God would turn the water into blood, if he refused to let Israel go. In the warning we can discern the difference between God and man. When a mortal harbors the intention to do an injury to an enemy, he lies in wait for the moment when he can strike an unexpected blow. But God is outspoken. He warned Pharaoh and the Egyptians in public whenever a plague was about to descend, and each warning was repeated by Moses for a period of three weeks, although the plague itself endured but a single week. As Pharaoh would not lay the warning to heart, the plague announced by Moses was let loose upon him and his people—the waters were turned into blood. It is a well- known proverb, "Beat the idols, and the priests are in terror." God smote the river Nile, which the Egyptians worshipped as their god, in order to terrify Pharaoh and his people and force them to do the Divine will.