…we must first scrutinize thoroughly anything appearing in our hearts or any saying suggested to us. Has it come purified from the divine and heavenly fire of the Holy Spirit? Or does it lean toward Jewish superstition? Is its surface piety something which has come down from bloated worldly philosophy? We must examine this most carefully, doing as the apostle bids us: ‘Do not believe in every spirit, but make sure to find out if spirits are from God’.
– John Cassian