How did false teaching and destructive leadership get into the church in Ephesus in the first place? Some might have blamed the false teachers, but Paul brings us to the real source of false teaching. Any teaching, whether explicitly evil or seemingly good; but is opposed to the teaching of the Spirit of God is actually the teaching of demons! Therefore, Paul calls us to be a people who know God’s Word well in order to discern well and live well in God’s world.
Now the Spirit expressly says that in later times some will depart from the faith by devoting themselves to deceitful spirits and teachings of demons, through the insincerity of liars whose consciences are seared, who forbid marriage and require abstinence from foods that God created to be received with thanksgiving by those who believe and know the truth. For everything created by God is good, and nothing is to be rejected if it is received with thanksgiving, for it is made holy by the word of God and prayer.
Additional passages: John 16:4-7, 12-15, Colossians 3:16, 1 Corinthians 7, Jeremiah 15:16