Exodus 8:6 – 7
New International Version (NIV)
6 So Aaron stretched out his hand over the waters of Egypt, and the frogs came up and covered the land. 7 But the magicians did the same things by their secret arts; they also made frogs come up on the land of Egypt.
From BibleGateway.com: http://www.biblegateway.com/passage/?search=Exodus+8.6-7&version=NIV