"And certainly We overtook Pharaoh's people with droughts and diminution of fruits that they might be mindful. But when good befell them they said: This is due to us. And when evil afflicted them, they attributed it to the ill-luck of Moses and those with him. Surely their evil fortune is only from Allah, but most of them know not. And they said: Whatever sign thou mayest bring to us to charm us therewith we shall not believe in thee. So We sent upon them widespread death, and the locusts and the lice and the frogs and the blood -- clear signs. But they behaved haughtily and they were a guilty people. And when the plague fell upon them, they said: O Moses, pray for us to thy Lord as He has made promise with thee. If thou remove the plague from us, we will certainly believe in thee and will let the Children of Israel go with thee. But when We removed the plague from them till a term which they should attain, lo they broke (their promise)."