'Believers' in the Bible

Yet when we are among mature believers we do speak words of wisdom; a wisdom not belonging, however, to the present age nor to the leaders of the present age who are soon to pass away.

If anyone destroys the temple of God [corrupting it with false doctrine], God will destroy the destroyer; for the temple of God is holy (sacred), and that is what you are.

Do you not know that the saints (God’s people) will [one day] judge the world? If the world is to be judged by you, are you not competent to try trivial (insignificant, petty) cases?

However, not all [believers] have this knowledge. But some, being accustomed [throughout their lives] to [thinking of] the idol until now [as real and living], still eat food as if it were sacrificed to an idol; and because their conscience is weak, it is defiled (guilty, ashamed).

But take care lest this liberty of yours should prove a hindrance to the progress of weak believers.

It follows that speaking in other languages is intended as a sign, not for believers but for unbelievers. But prophecy is not for unbelievers but for believers.