John Gill Commentary 1 Samuel 29

Now the Philistines gathered together all their armies to
Aphek
Not the city in the tribe of Judah of that name, (Joshua 15:53) ; where the Philistines had a camp in the time of Samuel, (1 Samuel 4:1) ; but rather that in the tribe of Asher, (Joshua 19:30) ; unless there was one of this name in the tribe of Issachar, not mentioned, since it seems to have been near Jezreel and Shunem, which were both in that tribe, (Joshua 19:18) ;

and the Israelites pitched by a fountain which is in Jezreel ;
in the valley of Jezreel; of which (See Gill on Joshua 19:18) and (See Gill on Hosea 1:5).

And the lords of the Philistines passed on by hundreds, and by
thousands
Not that there were so many lords, for there were but five of them; but these marched, some at the head of hundreds with them, and others at the head of thousands:

but David and his men passed on in the rereward with Achish ;
who being the generalissimo brought up the rear, and David, whom he had appointed captain of his bodyguards, attended him with his men, which in point of gratitude he could not refuse; and yet was in the greatest strait and difficulty how to act, it being both against his conscience and his interest to fight against Israel, and was waiting and hoping for some appearance of Providence to deliver him out of this dilemma, and which was quickly seen.

But Abarbinel thinks David had no other notion in going to the battle, but of being the bodyguard of Achish, and accompanying him, and that he should not fight against Israel, nor for the Philistines: neither harm the one, nor help the other.

Then said the princes of the Philistines
To Achish; not those of the court of Achish, who were his subjects, but the confederate princes with him in this war, the lords of the other principalities, as appears by the freedom they took with him, (1 Samuel 29:4);

what [do] these Hebrews [here] ?
or Jews, as the Targum; what do you have to do with them, or they to be with you? men of another nation and religion, and known enemies to the Philistines:

and Achish said to the princes of the Philistines ;
in order to soften them, and reconcile them to these men, and their being with him:

[is] not this David the servant of Saul the king of Israel ;
between whom there had been a quarrel, and the former had fled from the latter to him:

which has been with me these days, or these years ;
had been with him many days, and he might say years, as he had been with him one whole year, and part of another, see (1 Samuel 27:7); and he might have known him longer, if he was the same Achish David first fled to; Kimchi interprets it, that he knew him as well as if he had been with him as many years as days:

and I have found no fault in him since he fell [to me] to this day ?
the affair of David's going against the Geshurites not being yet known by him, or, if it was, he approved of it, they being enemies of his; this shows that David behaved with a great deal of prudence to have such a character as this from a king of the Philistines.

And the princes of the Philistines were wroth with him
With Achish, for giving such a character of David, and taking his part, in order to detain him, if possible:

and the princes of the Philistines said unto him, make this fellow
return ;
they speak of him with contempt, and insist on it that Achish order him to turn back, and go no further with them:

that he may go again to his place which you have appointed him ;
to Ziklag, the place that Achish had given him for his residence, (1 Samuel 27:6) ; they did not desire to have him sent to his own country, and to Saul, since should a reconciliation be made between them, he would be of great service to Saul against them:

and let him not go down with us to battle ;
into the valley of Jezreel, where the Israelites had pitched:

lest in the battle he be an adversary to us :
and fall upon them behind, being in the rear, while they were engaging in the front with Israel:

for wherewith should he reconcile himself unto his master ?
to Saul he had offended, and fled from:

[should it] not [be] with the heads of these men ?
the Philistines; or unless by the heads of these men ^F13 ; he had no other way of making his peace with his master but by cutting off the heads of the Philistines; and therefore he was a dangerous man to take with them into the battle.

FOOTNOTES:

• F13: (yvarb alh) "nisi per capita", Noldius, p. 257. No. 1147.

[Is] not this David, of whom they sang one to another in dances Long ago:

saying, Saul slew his thousands, and David his ten thousands; so that he is an old sworn enemy of ours; and the more valiant and victorious he has been, the less is he to be trusted, see (1 Samuel 18:7) (21:11).