Pharaoh’s heart grows harder and harder, and in return, God’s plagues grow mightier and mightier. After showing His sovereignty over life and the animal kingdom, God now shows His sovereignty over bodily health and disease, as He brings pestilence to Egypt’s animals and boils on its people. In doing so, God shows that He does what He says, and that the sign of a soft and upright heart to God is one who not only hears what He says but responds accordingly.