Al-A'raf 7:135

Moses performed his prophetic mission in Egypt for about forty years. There were two parts of his mission—one, to give the message of the oneness of God to Pharaoh and secondly, to lead the Children of Israel out of Egypt, settle them in the Sinai Desert and give them religious training in that untainted atmosphere. The Children of Israel (the progeny of Joseph) at that time were in the the grip of the Copt ruler (Pharaoh). The Copts used to utilise them as labourers in their agricultural and construction works. So, the Copt rulers did not want the Israelites to leave Egypt. Initially, when Moses demanded that Pharaoh should allow the Children of Israel to leave Egypt along with him, Pharaoh and his courtiers gave his request a political colour and accused Moses of intending to remove the Copt from Egypt ( 7:110 ). This was absolutely meaningless, because Moses’s plan was to remove himself from Egypt. At that time Pharaoh and his companions had an inflated opinion of their power and that is why they saw even a straight proposition in a crooked way. But, in later stages, God subjected Pharaoh and his community to all types of calamities. For many years they had continuously to face famines; they had severe hail-storms with lightning and thunder; swarms of locusts invaded their country and ate up their crops and gardens and completely destroyed all greenery; lice so proliferated that clothes and beds became infested with them; and in the houses and on the pathways, frogs were hopping about everywhere; the water in the rivers and lakes became bloody. When Pharaoh and his community began to suffer these strange afflictions, they asked Moses to pray to his Lord to relieve them of these troubles, then they would allow the Children of Israel to leave with Moses. Moses’s demand, which had earlier appeared to the Copts as a political conspiracy to evict them, now appeared to them simply as a migration of the Children of Israel themselves.