"During the time of their encampment beside Jordan, Moses was preparing for the occupation of Canaan. In this work the great leader was fully employed; but to the people this time of suspense and expectation was most trying, and before many weeks had elapsed their history was marred by the most frightful departures from virtue and integrity. PP 454.1"
"And Israel abode in Shittim, and the people began to commit whoredom with the daughters of Moab. And they called the people unto the sacrifices of their gods: and the people did eat, and bowed down to their gods. And Israel joined himself unto Baal–peor: and the anger of the Lord was kindled against Israel."
EGW's description of the events during the encampment beside Jordan, specifically the departure from virtue and integrity, directly corresponds to the events described in Numbers 25:1-3.
"garb of friendship, so that they were not suspected, even by the guardians of the people. PP 454.2"
"He that hateth dissembleth with his lips, and layeth up deceit within him; When he speaketh fair, believe him not: for there are seven abominations in his heart."
Both passages deal with deception and hidden malice under a friendly facade. The EGW passage describes enemies hiding their true intentions, while Proverbs warns against trusting those who speak kindly but harbor deceit.
"At Balaam's suggestion, a grand festival in honor of their gods was appointed by the king of Moab, and it was secretly arranged that Balaam should induce the Israelites to attend. He was regarded by them as a prophet of God, and hence had little difficulty in accomplishing his purpose. Great numbers of the people joined him in witnessing the festivities. They ventured upon the forbidden ground, and were entangled in the snare of Satan. Beguiled with music and dancing, and allured by the beauty of heathen vestals, they cast off their fealty to Jehovah. As they united in mirth and feasting, indulgence in wine beclouded their senses and broke down the barriers of self-control. Passion had full sway; and having defiled their consciences by lewdness, they were persuaded to bow down to idols. They offered sacrifice upon heathen altars and participated in the most degrading rites. PP 454.3"
"And Israel abode in Shittim, and the people began to commit whoredom with the daughters of Moab."
EGW elaborates on the events that led to Israel's whoredom with the daughters of Moab, as mentioned in Numbers 25:1, providing a detailed account of Balaam's suggestion and the subsequent festival and idolatry.
"It was not long before the poison had spread, like a deadly infection, through the camp of Israel. Those who would have conquered their enemies in battle were overcome by the wiles of heathen women. The people seemed to be infatuated. The rulers and the leading men were among the first to transgress, and so many of the people were guilty that the apostasy became national. “Israel joined himself unto Baalpeor.” When Moses was aroused to perceive the evil, the plots of their enemies had been so successful that not only were the Israelites participating in the licentious worship at Mount Peor, but the heathen rites were coming to be observed in the camp of Israel. The aged leader was filled with indignation, and the wrath of God was kindled. PP 454.4"
"And Israel joined himself unto Baal–peor: and the anger of the Lord was kindled against Israel."
The EGW passage directly quotes Numbers 25:3, indicating a clear and intentional reference.