Tertullian, on 1Thess 5:21

“But prove all things; hold fast that which is good.”

“And therefore "heresies must needs be in order that they which are approved might be made manifest," both those who remained stedfast under persecution, and those who did not wander out of their way into heresy. For the apostle does not mean that those persons should be deemed approved who exchange their creed for heresy; although they contrariously interpret his words to their own side, when he says in another passage, "Prove all things; hold fast that which is good; " as if, after proving all things amiss, one might not through error make a determined choice of some evil thing.”

Imported from an open dataset — not yet checked against the printed edition.