Exodus 7:11-13 NIV

11 Pharaoh then summoned wise men and sorcerers,1 and the Egyptian magicians2 also did the same things by their secret arts:3

References for Exodus 7:11

12 Each one threw down his staff and it became a snake. But Aaron's staff swallowed up their staffs.
13 Yet Pharaoh's heart4 became hard and he would not listen5 to them, just as the LORD had said.

References for Exodus 7:13