Pharaoh said, “Who is Havayah [G-d] that I should heed His
voice and send forth Israel? I do not recognize
Havayah, nor will I send Israel forth.”
The Divine Name Havayah refers to G-d outside the context of His creation. In contrast, the Name Elokim refers to G-d the Creator, acting within nature.
Pharaoh did indeed believe in G-d as the creative force within nature, but he knew nothing of a G-d beyond nature. One of the laws of nature is that the strong can overpower and rule the weak, so, since the Egyptians were stronger than the Jews, Pharaoh felt that it was their G-d-given right to rule over them. He could not accept the possibility that there was a G-d beyond nature who could override the laws of nature and declare that the strong should release the weak from their rule, even against their will, simply because this is the right thing to do.
G-d sent Moses to show Pharaoh that G-d is not limited by the laws of nature. We, too, must listen to our inner “Moses,” telling our inner “Pharaoh” that there is a moral code beyond the laws of nature, through which we--by following it-- can indeed rise above our natural drives and inclinations.
—from Daily Wisdom 3