John Gill Commentary 1 Samuel 30:14

"We made a raid upon the South of the Cherethites, and upon that which belongeth to Judah, and upon the South of Caleb; and we burned Ziklag with fire." — 1 Samuel 30:14 (ASV)

We made an invasion [upon] the south of the Cherethites
The Philistines so called, or at least one nation of them, such that dwelt to the south of the land, (1 Samuel 30:16) ; (See Gill on Zephaniah 2:5);

and upon [the coast] which [belongeth] to Judah ;
the south of Judah, where David pretended he had been, and had spoiled, and which was now actually done by the Amalekites, (1 Samuel 27:10) ;

and upon the south of Caleb ;
that part of the tribe of Judah which belonged to Caleb the son of Jephunneh, and his posterity, and which was the southern part of it, (Joshua 15:19) ;

and we burnt Ziklag with fire ;
and then departed.