"Trust No One" or "Test All Things"

Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world.
- 1 John 4:1

Do not treat prophecies with contempt but test them all; hold on to what is good,  reject every kind of evil.
- 1 Thessalonians 5:20-22

But there were also false prophets among the people, just as there will be false teachers among you. They will secretly introduce destructive heresies, even denying the sovereign Lord who bought them---bringing swift destruction on themselves.
- 2 Peter 2:1

Not many of you should become teachers, my fellow believers, because you know that we who teach will be judged more strictly.
- James 3:1