For reference, what are the plagues of Egypt?
tl;dr: In Exodus, the second book of the Bible, God sent plagues to Egypt, through Moses, in order to convince the Pharoah to release the people of Israel from slavery. He finally relented on the 10th plague.
Note that it's been a long time since I've read Exodus and I might be fuzzy on the details. Someone more versed in the Bible can feel free to correct/upend me here.