Two Witness principle
Why the specific mention of 'an UNBELIEVING mate' in the WT quoted above? Because unbelievers lie, but a believing mate would not?
Why unbelieving, partly because the WTS deals with non-jws differently from jws. The WTS believes that they have jurisdiction of jws but not non-jws.
I was surprised when I realized the OT said that Israelites could sell a dead animal that had not been bled properly to a non-Israelite because they were not under the Law.
(Deuteronomy 14:21) 21 “YOU must not eat any body [already] dead. To the alien resident who is inside your gates you may give it, and he must eat it; or there may be a selling of it to a foreigner, because you are a holy people to Jehovah your God.. . .
*** w04 9/15 p. 26 par. 2 Highlights From the Book of Deuteronomy ***
14:21—Why could the Israelites give to an alien resident or sell to a foreigner an unbled dead animal that they themselves would not eat? In the Bible, the term “alien resident” could refer to a non-Israelite who became a proselyte or to a settler who lived by basic laws of the land but who did not become a worshiper of Jehovah. A foreigner and an alien resident who did not become proselytes were not under the Law and could use unbled dead animals in various ways. The Israelites were permitted to give or sell such animals to them. The proselyte, on the other hand, was bound by the Law covenant. As indicated at Leviticus 17:10, such a person was forbidden to eat the blood of an animal.