Rabbah - (Rab'bath, great.)
(1.) "Rabbath of the children of Ammon," the chief city and capital of the Ammonites, among the eastern hills, some 20 miles east of the Jordan, on the southern of the two streams which united with the Jabbok. Here the bedstead (translated as "sarcophagus" in NIV Archaeological Study Bible) of Og was preserved (Deut. 3:11), perhaps as a trophy of some victory gained by the Ammonites over the king of Bashan. After David had subdued all their allies in a great war, he sent Joab with a strong force to take their city. For two years it held out against its assailants. It was while his army was engaged in this protracted siege that David was guilty of that deed of shame which left a blot on his character and cast a gloom over the rest of his life. At length, having taken the "royal city" (or the "city of waters," 2 Sam. 12:27, i.e., the lower city on the river, as distinguished from the citadel), Joab sent for David to direct the final assault (11:1; 12:26-31). The city was given up to plunder, and the people were put to death, and "thus did he with all the cities of the children of Ammon." The destruction of Rabbath was the last of David's conquests. The crown of the king of Rabbah became David's crown. His kingdom now reached its farthest limits (2 Sam. 8:1-15; 1 Chr. 18:1-15). The capture of this city is referred to in Amos (1:14), Jeremiah (49:2, 3), and Ezekiel (21:20; 25:5).
(2.) A city in the hill country of Judah (Josh. 15:60), possibly the ruin Rubba, six miles north-east of Beit-Jibrin.
This article incorporates text from a publication now in the public domain: Easton, Matthew George (1897). "article name needed". Easton's Bible Dictionary (New and revised ed.). T. Nelson and Sons. Clark's Commentary and newer translations show that the text should say "made them slaves" and not that David killed them all.