How did David trick Achish?

Question

I got to this section this week and I feel like I'm missing something:

David and his men went up and raided the Geshurites, the Gizrites, and the Amalekites—who were the inhabitants of the region of Olam, all the way to Shur and to the land of Egypt.—When David attacked a region, he would leave no man or woman alive; he would take flocks, herds, asses, camels, and clothing. When he returned and came to Achish, Achish would ask, “Where did you raid today?” and David would reply, “The Negeb of Judah,” or “the Negeb of the Jerahmeelites,” or “the Negeb of the Kenites.” David would leave no man or woman alive to be brought to Gath; for he thought, “They might tell about us: David did this.” Such was his practice as long as he stayed in the territory of the Philistines. Achish trusted David. He thought: “He has aroused the wrath of his own people Israel, and so he will be my vassal forever.”—1^st Samuel 27:8-12 (NJPS)

I know that Negeb can mean the desert region south of Jerusalem or just "south". So it seems like David must be using the ambiguity to trick Achish. To really understand what's going on here, I'd like to know:

1. What did David mean by "The Negeb of Judah"?
2. What did Achish think David was saying?

And what's the significance of the Jerahmeelites and the Kenites?

Answer 1

David attacks the Geshurites, the Gezerites and the Amelikites, all traditional enemies of Judah and Israel and potential allies of Achish to the southwest. He left no one alive so that no prisoners would tell Achish who David was really attacking, that's the trick. When asked, David says that he attacked to the south (actually southwest) of Judah, south of Jerahmiel, south of the Kenites, which is true, that's where the Geshurites, Gezerites and Amelikites are, but the statement is misleading because Jerahmiel is a sub-tribe of Judah and the Kenites (Jethro's tribe) are an allied tribe of Israel. It gives Achish the incorrect impression that David has committed acts against his own people that will prevent David from ever returning to Judah when in fact David has robbed Achish of his strategic depth. Achish is duped, as the final verse indicates. What he thought has happened to David has actually happened to him.

The verses make for hard reading to the modern ear, David leaving no one alive. I think that we need to read the verses assuming the commandment to destroy the Amelikites. This increase the irony of the ruse, as David will be able to claim this as a victory when he returns to Judah.