Adam Clarke on 1 Chronicles 20:8

These were born unto the giant in Gath - "These were born להרפא leharapha, to that Rapha in Gath, or to Arapha." So the Vulgate, Septuagint, and Chaldee.

The compiler of these books passes by also the incest of Amnon with his sister Tamar, and the rebellion of Absalom, and the awful consequences of all these. These should have preceded the fourth verse. These facts could not be unknown to him, for they were notorious to all; but he saw that they were already amply detailed in books which were accredited among the people, and the relations were such as no friend to piety and humanity could delight to repeat. On these grounds the reader will give him credit for the omission. See on 1Chr 20:1 (note).