For all the church scenes, hymns on the soundtrack, and other Christian accoutrements that adorn the film, few characters in Killers seem to believe the Bible. Ernest doesn’t believe because he wasn't seen at church at all - although has dripped off his wife to church once.
Probably 3 or more lessons in this film "TGC:
1) “Whoever is greedy for unjust gain troubles his own household”).
2) Proverbs 13:20 (“Whoever walks with the wise becomes wise, but the companion of fools will suffer harm”) or Corinthians 15:33 (“Bad company ruins good morals”).
Ernest was ruined by his uncle while Mollie was ruined by Ernest.
3) Timothy 6:10 (“The love of money is a root of all kinds of evils”)