Deuteronomy 13:3
Deuteronomy 13:33you must not listen to the words of that prophet or dreamer. For the LORD your God is testing you to find out whether you love Him with all your heart and with all your soul.
Used to warn Witnesses against being drawn away by teachers whose claims may look impressive. In practice the warning is directed at apostates and at Christendom, and the "testing" is understood as Jehovah proving the loyalty of his people — loyalty which the organisation identifies closely with remaining within it.
The verse says God is testing whether you love him with all your heart and soul. Notice where the loyalty is directed: to God himself, not to a teacher, a movement, or an institution. That distinction is the whole burden of the chapter — a prophet who redirects devotion is false however impressive his credentials. Two things follow. First, the test is one a person is expected to apply, not merely submit to. Moses is telling Israel to evaluate what they are being told. The Bereans are commended for the same instinct at — they checked an apostle's preaching against the Scriptures, and Luke calls them noble-minded for it. Paul did not object. Second, the test is symmetrical or it is nothing. If Deuteronomy is the right tool for assessing religious claims, then it applies to whoever is making one, including the movement doing the assessing. Ask gently whether a Witness feels free to run the test in both directions — and if not, what that tells them. Compare , , .