Charles Ellicott Commentary 1 Samuel 23:4

"Then David inquired of Jehovah yet again. And Jehovah answered him, and said, Arise, go down to Keilah; for I will deliver the Philistines into thy hand." — 1 Samuel 23:4 (ASV)

David enquired ... yet again. —This second enquiry, made to inspire his little army with confidence before embarking on the seemingly desperate attempt, was, as in the previous case mentioned in 1 Samuel 23:2, no doubt through the prophet Gad. Abiathar had not yet arrived with the ephod.