Try sharing with Mormons Eph 2:8. I did this once at work and they (both a Mormon and a JW tried to to argue with me). They believe in works based salvation. Which is impossible.
Eph 2:8-9 is a great verse to share with LDS. They usually counter with James 2:14-17 saying works are required (faith without works is dead), but if you can get them to look at the context of James, he isn’t teaching salvation by works at all. That stumps them.