"On one occasion Jehoshaphat visited the king of Israel at Samaria. Special honor was shown the royal guest from Jerusalem, and before the close of his visit he was persuaded to unite with the king of Israel in war against the Syrians. Ahab hoped that by joining his forces with those of Judah he might regain Ramoth, one of the old cities of refuge, which, he contended, rightfully belonged to the Israelites. PK 195.1"
"Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness? and what communion hath light with darkness?"
The EGW passage describes Jehoshaphat's alliance with Ahab, which directly violates the principle of not being unequally yoked with unbelievers. The alliance led to compromise and danger for Jehoshaphat. The verse from 2 Corinthians warns against such alliances.
Although Jehoshaphat in a moment of weakness had rashly promised to join the king of Israel in his war against the Syrians, yet his better judgment led him to seek to learn the will of God concerning the undertaking. “Inquire, I pray thee, at the word of the Lord today,” he suggested to Ahab. In response, Ahab called together four hundred of the false prophets of Samaria, and asked of them, “Shall we go to Ramoth-gilead to battle, or shall I forbear?” And they answered, “Go up; for God will deliver it into the kings's hand.” Verses 4, 5 . PK 195.2 Unsatisfied, Jehoshaphat sought to learn for a certainty the will of God. “Is there not here a prophet of the Lord,” he asked, “that we might inquire of him?” Verse 6 . “There is yet one man, Micaiah the son of Imlah, by whom we may inquire of the Lord,” Ahab answered; “but I hate him; for he doth not prophesy good concerning me, but evil.” 1 Kings 22:8 . Jehoshaphat was firm in his request that the man of God be called; and upon appearing be…
"And the king of Israel said unto Jehoshaphat, There is yet one man, Micaiah the son of Imlah, by whom we may enquire of the Lord: but I hate him; for he doth not prophesy good concerning me, but evil. And Jehoshaphat said, Let not the king say so."
Ellen White directly references 1 Kings 22:8 in this passage.