"As the years rolled on, and he wandered with his flocks in solitary places, pondering upon the oppressed condition of his people, he recounted the dealings of God with his fathers and the promises that were the heritage of the chosen nation, and his prayers for Israel ascended by day and by night. Heavenly angels shed their light around him. Here, under the inspiration of the Holy Spirit, he wrote the book of Genesis. The long years spent amid the desert solitudes were rich in blessing, not alone to Moses and his people, but to the world in all succeeding ages. PP 251.1"
"Now Moses kept the flock of Jethro his father in law, the priest of Midian: and he led the flock to the backside of the desert, and came to the mountain of God, even to Horeb."
Both passages discuss Moses tending flocks and his time in the desert. The EGW passage adds details about his spiritual development and writing Genesis, which are plausible inferences based on the biblical narrative and tradition.
“And it came to pass in process of time, that the king of Egypt died: and the children of Israel sighed by reason of the bondage, and they cried, and their cry came up unto God by reason of the bondage. And God heard their groaning, and God remembered His covenant with Abraham, with Isaac, and with Jacob. And God looked upon the children of Israel, and God had respect unto them.” The time for Israel's deliverance had come. But God's purpose was to be accomplished in a manner to pour contempt on human pride. The deliverer was to go forth as a humble shepherd, with only a rod in his hand; but God would make that rod the symbol of His power. Leading his flocks one day near Horeb, “the mountain of God,” Moses saw a bush in flames, branches, foliage, and trunk, all burning, yet seeming not to be consumed. He drew near to view the wonderful sight, when a voice from out of the flame called him by name. With trembling lips he answered, “Here am I.” He was warned not to approach irreverently: “…
"And it came to pass in process of time, that the king of Egypt died: and the children of Israel sighed by reason of the bondage, and they cried, and their cry came up unto God by reason of the bondage. And God heard their groaning, and God remembered his covenant with Abraham, with Isaac, and with Jacob. And God looked upon the children of Israel, and God had respect unto them."
The EGW passage directly quotes Exodus 2:23-25, making it a clear and explicit allusion.