And it came to pass, when David and his men were come to Ziklag on the third day, that the Amalekites had invaded the south, and Ziklag, and smitten Ziklag, and burned it with fire; On the third day - This was the third day after he had left the Philistine army at Aphek. Calmet supposes that Aphek was distant from Ziklag more than thirty leagues.
The Amalekites had invaded - These were, doubtless, a travelling predatory horde, who, availing themselves of the war between the Philistines and the Israelites, plundered several unprotected towns, and among them Ziklag. It is likely they had not heard of what David did to some of their tribes, else they would have avenged themselves by slaying all they found in Ziklag.