David conducts raids from Ziklag
While he was living among the Philistines, David raided the Geshurites, Girzites and Amalekites. The Philistines thought he was raiding Israel.
Key passages
1 Sa 27:8–12

Now David and his men went up and raided the Geshurites and the Girzites and the Amalekites, for they had been living in the land for a long time in the direction of Shur and as far as the land of Egypt. So David struck the land and did not leave a man or a woman alive; he took the sheep, …