There are some commentators who take this verse to imply that Keilah was not part of Judah at this time.1 If this was the case, then it is not clear why the Philistines would be raiding their own village nor why the Lord would want David to go and intervene.
3 But David’s men said to him, “Behold, we are afraid here in Judah; how much more then if we go to Keilah against the armies of the Philistines?”