Charles Ellicott Commentary 2 Samuel 6:1

"And David again gathered together all the chosen men of Israel, thirty thousand." — 2 Samuel 6:1 (ASV)

Again, David gathered. —The word “again” should be transposed: “David gathered together again”—referring to the former military musters. In 1 Chronicles 13:1–4, mention is made of the consultations with the leaders of Israel which preceded this gathering, and the gathering itself is there (2 Samuel 6:5) said to be of “all Israel.” But “all Israel” was evidently represented by the thirty thousand (the Septuagint reads seventy thousand) of its more prominent men.