"Heathen nations had reproached the Lord and His people because the Hebrews had failed to take possession of Canaan, as they expected, soon after leaving Egypt. Their enemies had triumphed because Israel had wandered so long in the wilderness, and they had mockingly declared that the God of the Hebrews was not able to bring them into the Promised Land. The Lord had now signally manifested His power and favor in opening the Jordan before His people, and their enemies could no longer reproach them. PP 486.1"
"Because the Lord was not able to bring this people into the land which he sware unto them, therefore he hath slain them in the wilderness."
Both passages address the idea that the surrounding nations doubted God's ability to bring Israel into the Promised Land. The EGW passage directly references this reproach.
"“On the fourteenth day of the month at even,” the Passover was celebrated on the plains of Jericho. “And they did eat of the old corn of the land on the morrow after the Passover, unleavened cakes, and parched corn in the selfsame day. And the manna ceased on the morrow after they had eaten of the old corn of the land; neither had the children of Israel manna any more; but they did eat of the fruit of the land of Canaan.” The long years of their desert wanderings were ended. The feet of Israel were at last treading the Promised Land. PP 486.2"
"And the children of Israel encamped in Gilgal, and kept the passover on the fourteenth day of the month at even in the plains of Jericho."
The EGW passage directly quotes and elaborates on Joshua 5:10, describing the Passover celebration in the plains of Jericho.