"Chapter 36—In the Wilderness For nearly forty years the children of Israel are lost to view in the obscurity of the desert. “The space,” says Moses, “in which we came from Kadesh-barnea, until we were come over the brook Zered, was thirty and eight years; until all the generation of the men of war were wasted out from among the host, as the Lord sware unto them. For indeed the hand of the Lord was against them, to destroy them from among the host, until they were consumed.” Deuteronomy 2:14, 15 . PP 406"
"And the space in which we came from Kadesh–barnea, until we were come over the brook Zered, was thirty and eight years; until all the generation of the men of war were wasted out from among the host, as the Lord sware unto them. For indeed the hand of the Lord was against them, to destroy them from among the host, until they were consumed."
EGW directly quotes Deuteronomy 2:14-15.
Yet the continuance of the tabernacle service testified that God had not utterly forsaken His people. And His providence still supplied their wants. “The Lord thy God hath blessed thee in all the works of thy hand,” said Moses, in rehearsing the history of their wanderings. “He knoweth thy walking through this great wilderness; these forty years the Lord thy God hath been with thee; thou hast lacked nothing.” And the Levites’ hymn, recorded by Nehemiah, vividly pictures God's care for Israel, even during these years of rejection and banishment: “Thou in Thy manifold mercies forsookest them not in the wilderness: the pillar of the cloud departed not from them by day, to lead them in the way; neither the pillar of fire by night, to show them light, and the way wherein they should go. Thou gavest also Thy good Spirit to instruct them, and withheldest not Thy manna from their mouth, and gavest them water for their thirst. Yea, forty years didst Thou sustain them in the wilderness; ... thei…
"Yet thou in thy manifold mercies forsookest them not in the wilderness: the pillar of the cloud departed not from them by day, to lead them in the way; neither the pillar of fire by night, to shew them light, and the way wherein they should go. Thou gavest also thy good spirit to instruct them, and withheldest not thy manna from their mouth, and gavest them water for their thirst. Yea, forty years didst thou sustain them in the wilderness, so that they lacked nothing; their clothes waxed not old, and their feet swelled not."
Ellen White directly references Nehemiah 9:19-21 in this passage.