A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
1 Kings (1 Samuel) 30:1
sa1 30:1THE AMALEKITES SPOIL ZIKLAG. (Sa1 30:1-5)
Amalekites had invaded the south, and Ziklag, and smitten Ziklag--While the strength of the Philistine forces was poured out of their country into the plain of Esdraelon, the Amalekite marauders seized the opportunity of the defenseless state of Philistia to invade the southern territory. Of course, David's town suffered from the ravages of these nomad plunderers, in revenge for his recent raid upon their territory.
1 Kings (1 Samuel) 30:2
sa1 30:2they slew not any, either great or small, but carried them away--Their conduct seems to stand in favorable contrast to that of David (Sa1 27:11). But their apparent clemency did not arise from humane considerations. It is traceable to the ancient war usages of the East, where the men of war, on the capture of a city, were unsparingly put to death, but there were no warriors in Ziklag at the time. The women and boys were reserved for slaves, and the old people were spared out of respect to age.
1 Kings (1 Samuel) 30:3
sa1 30:3David and his men came to the city, and, behold, it was burned with fire--The language implies that the smoke of the conflagration was still visible, and the sacking very recent.
1 Kings (1 Samuel) 30:6
sa1 30:6BUT DAVID, ENCOURAGED BY GOD, PURSUES THEM. (Sa1 30:6-15)
David was greatly distressed--He had reason, not only on his own personal account (Sa1 30:5), but on account of the vehement outcry and insurrectionary threats against him for having left the place so defenseless that the families of his men fell an unresisting prey to the enemy. Under the pressure of so unexpected and widespread a calamity, of which he was upbraided as the indirect occasion, the spirit of any other leader guided by ordinary motives would have sunk;
but David encouraged himself in the LORD his God--His faith supplied him with inward resources of comfort and energy, and through the seasonable inquiries he made by Urim, he inspired confidence by ordering an immediate pursuit of the plunderers.
1 Kings (1 Samuel) 30:9
sa1 30:9came to the brook Besor--now Wady Gaza, a winter torrent, a little to the south of Gaza. The bank of a stream naturally offered a convenient rest to the soldiers, who, through fatigue, were unable to continue the pursuit.
1 Kings (1 Samuel) 30:11
sa1 30:11they found an Egyptian in the field, and brought him to David--Old and homeborn slaves are usually treated with great kindness. But a purchased or captured slave must look to himself; for, if feeble or sick, his master will leave him to perish rather than encumber himself with any additional burden. This Egyptian seems to have recently fallen into the hands of an Amalekite, and his master having belonged to the marauding party that had made the attack on Ziklag, he could give useful information as to the course taken by them on their return.
1 Kings (1 Samuel) 30:14
sa1 30:14the Cherethites--that is, the Philistines (Eze 25:16; Zep 2:5).
1 Kings (1 Samuel) 30:15
sa1 30:15Swear unto me by God--Whether there was still among these idolatrous tribes a lingering belief in one God, or this Egyptian wished to bind David by the God whom the Hebrews worshipped, the solemn sanction of an oath was mutually recognized.
1 Kings (1 Samuel) 30:16
sa1 30:16AND RECOVERS HIS TWO WIVES AND ALL THE SPOIL. (1Sa. 30:16-31)
they were spread abroad upon all the earth--Believing that David and all his men of war were far away, engaged with the Philistine expedition, they deemed themselves perfectly secure and abandoned themselves to all manner of barbaric revelry. The promise made in answer to the devout inquiries of David (Sa1 30:8) was fulfilled. The marauders were surprised and panic-stricken. A great slaughter ensued--the people as well as the booty taken from Ziklag was recovered, besides a great amount of spoil which they had collected in a wide, freebooting excursion.
1 Kings (1 Samuel) 30:21
sa1 30:21David came to the two hundred men, which were so faint that they could not follow--This unexpected accession of spoil was nearly proving an occasion of quarrel through the selfish cupidity of some of his followers, and serious consequences might have ensued had they not been prevented by the prudence of the leader, who enacted it as a standing ordinance--the equitable rule--that all the soldiers should share alike (see Num 31:11; see on Num 31:25).
1 Kings (1 Samuel) 30:26
sa1 30:26when David came to Ziklag, he sent of the spoil to the elders of Judah--This was intended as an acknowledgment to the leading men in those towns and villages of Judah which had ministered to his necessities in the course of his various wanderings. It was the dictate of an amiable and grateful heart; and the effect of this well-timed liberality was to bring a large accession of numbers to his camp (Ch1 12:22). The enumeration of these places shows what a numerous and influential party of adherents to his cause he could count within his own tribe [Sa1 30:27-31].