1 Chronicles 18:12-13 meaning
1 Chronicles 18:12-13 completes the circle of David's conquests on the southern border: Moreover Abishai the son of Zeruiah defeated 18,000 Edomites in the Valley of Salt (v 12). Abishai was David's nephew, the son of his sister Zeruiah and the brother of Joab (1 Chronicles 2:16), and chief of the thirty among David's mighty men (1 Chronicles 11:20-21). The Valley of Salt most likely lay in the barren region south of the Dead Sea, on the road into Edom. Edom descended from Esau (Genesis 36:1), and the brother nations had been at odds since Edom refused Israel passage in the wilderness (Numbers 20:14-21).
The credit for this battle is assigned three ways in Scripture. 2 Samuel 8:13 says "David made a name for himself when he returned from killing 18,000 Arameans in the Valley of Salt," where "Arameans" and "Edomites" differ by one Hebrew letter and the location fixes the enemy as Edom. The title of Psalm 60 says that "Joab returned, and smote twelve thousand of Edom in the Valley of Salt." The three accounts fit together once the chain of command is kept in view. Abishai led the field force, Joab commanded the army, and David was king; a victory belonged to each according to his office, and the two figures may count different phases of the same campaign.
Psalm 60 itself shows the cost of the fight: David wrote it when Israel had been "rejected" and "broken" and prayed, "Who will bring me into the besieged city? Who will lead me to Edom?" before answering his own question, "Through God we shall do valiantly, and it is He who will tread down our adversaries" (Psalm 60:1, 9, 12). The flat statement of victory in Chronicles rests on a hard-won battle.
The result matched the others: Then he put garrisons in Edom, and all the Edomites became servants to David. And the LORD helped David wherever he went (v 13). Edom joined Moab and Aram under David's garrisons, and the chronicler closes the campaign record with his refrain from 1 Chronicles 18:6, the LORD helped David wherever he went (v 13). The repetition brackets the wars of verses 3 through 13 and assigns the victories to one source. Readers who remember God's word in the covenant, "I will subdue all your enemies" (1 Chronicles 17:10), are meant to hear this second refrain as the signature on a completed promise.
Edom's subjection fulfilled old words and foreshadowed later ones. Isaac had told Esau, "Your brother you shall serve" (Genesis 27:40), and Balaam had said, "Edom shall be a possession" when the scepter rose from Israel (Numbers 24:18).
The prophets took David's conquest as a pattern for the future kingdom of David's Son. Amos promised that God would "raise up the fallen booth of David" so that His people "may possess the remnant of Edom and all the nations who are called by My name" (Amos 9:11-12), and James quoted that promise at the Jerusalem council to show that God was now gathering the Gentiles into the kingdom of the risen Christ (Acts 15:15-18). The initial fulfillment was Edom under David's garrisons; the ultimate fulfillment, on James's reading, is the nations coming under the rule of Jesus through the gospel. The two share one feature: in both, the LORD does the subduing, and the people of God receive what He has won.