God had sent judgments upon Israel for yielding to the enticements of the Midianites; but the tempters were not to escape the wrath of divine justice. The Amalekites, who had attacked Israel at Rephidim, falling upon those who were faint and weary behind the host, were not punished till long after; but the Midianites who seduced them into sin were speedily made to feel God's judgments, as being the more dangerous enemies. “Avenge the children of Israel of the Midianites” ( Numbers 31:2 ), was the command of God to Moses; “afterward shalt thou be gathered unto thy people.” This mandate was immediately obeyed. One thousand men were chosen from each of the tribes and sent out under the leadership of Phinehas. “And they warred against the Midianites, as the Lord commanded Moses.... And they slew the kings of Midian, beside the rest of them that were slain; ... five kings of Midian: Balaam also the son of Beor they slew with the sword.” Verses 7, 8 . The women also, who had been made captiv…
Ellen White directly references Numbers 31:2 in this passage.
Numbers 31:8"And they slew the kings of Midian, beside the rest of them that were slain; namely, Evi, and Rekem, and Zur, and Hur, and Reba, five kings of Midian: Balaam also the son of Beor they slew with the sword."
"Balaam witnessed the success of his diabolical scheme. He saw the curse of God visited upon His people, and thousands falling under His judgments; but the divine justice that punished sin in Israel did not permit the tempters to escape. In the war of Israel against the Midianites, Balaam was slain. He had felt a presentiment that his own end was near when he exclaimed, “Let me die the death of the righteous, and let my last end be like his!” But he had not chosen to live the life of the righteous, and his destiny was fixed with the enemies of God. PP 451.6"
The EGW passage directly states that Balaam was slain in the war against the Midianites, which is explicitly stated in Numbers 31:8.