Compare the marginal references. It appears 1 Samuel 14:48 that this expedition against Amalek was not made without fresh provocation. Probably some incursion similar to that described in 1 Samuel 30 was made by them upon the south country at a time when they thought the Israelites were weakened by their contests with the Philistines.
Related Commentaries of 1 Samuel 15:2
1 Samuel 15:2
2 Thus saith the LORD of hosts, I remember that which Amalek did to Israel, how he laid wait for him in the way, when he came up from Egypt.