Took his head. — There is no difficulty with the repetition in 2 Samuel 4:7 of what has been already mentioned inverse 6, for it is common in the Scripture narratives to repeat statements when any additional fact (as here, the carrying off of the head) is to be mentioned. (See, e.g., 2 Samuel 3:22-23, where Joab’s arrival is twice mentioned, and 2 Samuel 5:1-3, where the mention of the assembly at Hebron is repeated.)
Through the plain. — As in 2 Samuel 2:29, the Arabah, or valley of the Jordan, the natural way from Mahanaim to Hebron.