1 Chronicles 12:16

“And there came of the men of Benjamin, and of Judah, etc.] Besides those before mentioned, (<131202>1 Chronicles 12:2), to the hold unto David; the same as in (<131208>1 Chronicles 12:8).”

“the children of Benjamin and Judah--It is probable that the Benjamites invited the Judahites to accompany them, in order to prevent David being suspicious of them. Their anticipations, as the result showed, were well founded. He did suspect them, but the doubts of David as to their object in repairing to him, were promptly dispelled by Amasai or Amasa, who, by the secret impulse of the Spirit, assured him of their strong attachment and their zealous service from a unanimous conviction that his cause was owned and blessed of God (Sa1 18:12-14).”

“the children: Ch1 12:2 the hold: Ch1 12:8 1 Chronicles 12:17”

“There came to David in the mountain-fastness also men of Benjamin and Judah (cf. Ch1 12:8). Their names are not in the lists, possibly because they were not handed down in the historical works made use of by the chronicler. At their head, as we learn from Ch1 12:18, stood Amasai, chief of the thirty, i.e., of the corps formed of the thirty heroes (see Ch1 11:11), although his name does not occur in the catalogue, 1 Chron 11. According to this, Amasai must have occupied a very important position under David; but since the name עמשׂי is not elsewhere mentioned in the history of David, the older commentators have conjectured that עמשׂי may have been the same person as עמשׂא, son of Abigail (…”