The prophets of Baal were not the only false prophets in Israel in the days of Elijah, as we see in I Kings 22. As Ahab and King Jehoshaphat of Judah were seeking guidance before a potential battle, :11 says “Then Zedekiah the son of Chenaanah made horns of iron for himself and said, ‘Thus says YHWH, “With these you will gore the Arameans until they are consumed.”‘” So Zedekiah the son of Chenaanah was not a prophet of Baal, but supposedly a prophet of YHWH. (We see the same thing from other false prophets in :12 too) So the problem in Israel in the days of Ahab was not only the prophets of Baal, but supposed prophets of YHWH who spoke falsehood instead of His truth. We have the same basic problem today.
The false assertions of the enemy will assail churches today from the same two sources: both outside and inside the faith. There will be those, who, like the prophets of Baal, attack the truths of God from an entirely different religious perspective, serving other gods. But also as in Jehoshaphat’s time, there will be those today who claim to speak for the God of the Bible, but who like Zedekiah do not share His word in truth.
In Acts 20:29-30 the Apostle Paul said that after his departure “savage wolves will come in”, and also “from among your own selves men will arise, speaking perverse things.” He was warning God’s people against the dual threats of the enemy against the truth.
Satan’s attacks will come both from false religions outside of Christianity, and from false teachers and prophets supposedly inside the faith. Wise and discerning Christians must be on the alert against both.