Charles Ellicott Commentary 1 Samuel 30:12

"And they gave him a piece of a cake of figs, and two clusters of raisins: and when he had eaten, his spirit came again to him; for he had eaten no bread, nor drunk any water, three days and three nights." — 1 Samuel 30:12 (ASV)

Three days and three nights. — This indicated the amount of head start the Amalekite leader had with the plunder. It is easy to understand that there was no time to lose. The cruelty of the Amalekites to their slaves was the cause of their ultimate defeat, for even with the very considerable head start they already had, the pursuit would have been utterly hopeless if David had not been certain of their route through the Egyptian's information.