So, Deuteronomy 23: It's all about who you can and can't hang with. You can't associate with people who are castrated, with Ammonites, or Moabites. Even if they're bribing you with food and water, don't take it! The same goes for Edomites - no alliance there. Oh, and don't forget to pay your hired help on time - no waiting until the next day. It's like, c'mon, people, show some decency.