"And the Lord sent fiery serpents among the people, and they bit the people; and much people of Israel died."
The EGW passage refers to the 'venomous creatures' which is a clear reference to the fiery serpents in Numbers 21:6. While not a direct quote, the connection is undeniable.
"Now there was terror and confusion throughout the encampment. In almost every tent were the dying or the dead. None were secure. Often the silence of night was broken by piercing cries that told of fresh victims. All were busy in ministering to the sufferers, or with agonizing care endeavoring to protect those who were not yet stricken. No murmuring now escaped their lips. When compared with the present suffering, their former difficulties and trials seemed unworthy of a thought. PP 429.2"
"And the Lord sent fiery serpents among the people, and they bit the people; and much people of Israel died."
The EGW passage describes the scene after the serpents were sent, which is described in Numbers 21:6. The description of death and suffering aligns with the verse.
"The people now humbled themselves before God. They came to Moses with their confessions and entreaties. “We have sinned,” they said, “for we have spoken against the Lord, and against thee.” Only a little before, they had accused him of being their worst enemy, the cause of all their distress and afflictions. But even when the words were upon their lips, they knew that the charge was false; and as soon as real trouble came they fled to him as the only one who could intercede with God for them. “Pray unto the Lord,” was their cry, “that He take away the serpents from us.” PP 429.3"
"Therefore the people came to Moses, and said, We have sinned, for we have spoken against the Lord, and against thee; pray unto the Lord, that he take away the serpents from us. And Moses prayed for the people."
The EGW passage directly quotes Numbers 21:7.