For a while, Moses was a shepherd. He worked for his father-in-law, the way his ancestor Jacob had worked for his (though Moses had a far better father-in-law than Jacob did). Jacob never really worked another job: we know he cooked; he was incredibly strong, so presumably he did physically demanding things; but the main thing always was that he was good with flocks and herds, very successful at it, diligent, hardworking if not always shrewd. He lived in exile all his life, at home a wanderer or away from it in settled country, or in Egyptian exile, till he found rest at last in a grave with his ancestors.
Moses, however, was trained in the court of Egypt. The Egyptians, we know, looked down on those who kept herds and flocks: "for every shepherd is an abomination to the Egyptians,” as Joseph explained to his family in Genesis 46:34. When Moses identified with his oppressed people, the Hebrews, and as a result of his rash actions had to flee, he ended up a shepherd like his ancestors had been.
The first part of his life, his first forty years were lived in what were probably the best circumstances anybody could have in that ancient time of the world, materially. But he must also have lived with an inner conflict of identity: the training his mother no doubt gave him never to forget his true origins; the patently Hebrew name; a protegee of Pharaoh's daughter, among the elite of the world's elite; his outer appearance as Egyptian as a Sphinx, and as enigmatically so, since inwardly and from his earliest memories he knew that he belonged to the people Egypt exploited and oppressed.
It must have been a relief, along with disappointment, to find himself away from the growing inner struggle. It burst forth in that murder which marked the end of his Egyptian identity and caused his flight. Then came the forty years during which he kept the flocks of Jethro his father-in-law, having left everything behind. He must have given up on his people, to some extent: we know from the enigmatic story in chapter four that Moses even neglected to circumcise his children. What wildernesses must those forty years have been for one trained in all the wisdom of Egypt?
"I am a sojourner in a foreign land," he remarks on the occasion of celebrating his firstborn. Was it an ironic remark? When had he ever lived in his own country? An exile from his family, an exile from his circumstances, an exile from all the world when God finds him in chapter three. And when would he ever, until he came to that country John Bunyan has called Immanuel's Land, find a home?
Forty years into his new job Moses leads the animals into uninhabited land in search of forage. He lives in Midian, east of Egypt, but he is heading west. And it is only then, that momentous first verse of chapter three tells us, that he came at last to Horeb, the mountain of God.